Sunday

July 31, 2016
Total # Posts: 2,153

**pre algebra**

L = larger numbr S = smaller number The difference between two numbers is 44 mean: L - S = 44 Five times the smaller is equal to 8 more than the larger mean: 5 S = L + 8 Now youust solve sytem of two equation with two unknow. L - S = 44 5 S = L + 8 L - S = 44 Add S to both ...
*July 30, 2016*

**Math**

4*15-11+8-2=20 ______________________ 4*1(5-1)-1(+8/-2)= 4 * 1 * 4 - 1 * ( - 4 ) = 16 + 4 = 20
*July 30, 2016*

**Maths**

1st term: n = 1 Sn = 3 n - 2 S1 = 3 * 1 - 2 = 3 - 2 = 1 3rd term: n = 3 Sn = 3 n - 2 S3 = 3 * 3 - 2 = 9 - 2 = 7 5th term: n = 5 Sn = 3 n - 2 S5 = 3 * 5 - 2 = 15 - 2 = 13
*July 30, 2016*

**pre cal**

A cubic function is a function of the form: f ( x ) = a ^ 3 + b x ^ 2 + c x + d You must find 4 coefficients: a , b , c , and d You now zero pionts: x = - 5 , y = 0 x = 2 , y = 0 and x = 4 , y = 0 You also know : f ( - 10 ) = - 4 Now put this values in equation: f ( x ) = a x...
*July 27, 2016*

**Math**

12 * 20 = 240
*July 23, 2016*

**Math**

n = 2 didit number a = tens b = ones So: n = 10 a + b The number exceeds the sum of digits by18 mean: n = a + b + 18 Now equalize exspressions for n. n = n 10 a + b = a + b + 18 Subtract b to both sides 10 a + b - b = a + b + 18 - b 10 a = a + 18 Subtract a to both sides 10 a...
*July 23, 2016*

**math**

3 / 7 = 15 / x Multiply both sides by x 3 x / 7 = 15 Multiply both sides by 7 3 x = 15 * 7 3 x = 105 Divide both sides by 3 x = 105 / 3 x = 35 3 / 7 = 15 / 35
*July 22, 2016*

**math**

1 h 45 min = 60 min + 45 min = 105 min 24 / 105 = 64 / x Muultiply both sides bx x 24 x / 105 = 64 Multiply both sides by 105 24 x = 64 * 105 24 x = 6720 Divide both sides by 24 x = 6720 / 24 = 280 min x = 240 min + 40 min = 4 * 60 min + 40 min = 4 h 40 min OR 64 / 24 = 8 * 8...
*July 22, 2016*

**Math**

a) 13 , 17 , 25 , 27 , 28 , x , 32 , 36 , 37 , 40 , y , 47 The median is the middle number. But there is no "middle" number, because there are an even number of numbers. In this case, the median is the mean (the usual average) of the middle two values: The median...
*July 22, 2016*

**math**

x = present age In five years time thabo will be three times as old as he was nine years ago, mean: 5 + x = 3 ( x - 9 ) 5 + x = 3 x - 27 Subtract x to both sides 5 + x - x = 3 x - 27 - x 5 = 2 x - 27 Add 27 to both sides 5 + 27 = 2 x - 27 + 27 32 = 2 x Divide both sides by 2 ...
*July 22, 2016*

**Math**

x ^ - 1/4 = 4 ^ -1/2 mean: 1 / fourth root of x = 1 / square root of 4 1 / fourth root of x = 1 / 2 Taking reciprocial of both sides: fourth root of x = 2 Rise both sides to the power of four x = 2 ^ 4 x = 16 q^ 1/2 = x mean : square root of q = x Rise both sides to the power ...
*July 19, 2016*

**Math**

c and d are positive consecutive odd integers mean : c = d + 2 becouse : if d are odd integers, next integer are d + 2 So: c + d = 240 d + d + 2 = 240 2 d + 2 = 240 Subtract 2 to both sides 2 d + 2 - 2 = 240 - 2 2 d = 238 Divide both sides by2 d = 238 / 2 = 119 c = d + 2 c = ...
*July 19, 2016*

**Math**

| a - 2 | = 9 a - 2 = + OR - 9 1 solution: a - 2 = 9 Add 2 to both sides a - 2 + 2 = 9 + 2 a = 11 2 solution: a - 2 = - 9 Add 2 to both sides a - 2 + 2 = - 9 + 2 a = - 7 | w - 1 | = 6 w - 1 = + OR - 6 1 solution: w - 1 = 6 Add 1 to both sides w - 1 = 6 + 1 w = 7 2 solution: w...
*July 19, 2016*

**Math**

first number: a second number: a + 1 third number: a + 2 fourth number: a + 3 fifth number: a + 4 a + a + 1 + a + 2 + a + 3 + a + 4 = 80 5 a + 10 = 80 Subtract 10 to both sides 5 a + 10 - 10 = 80 - 10 5 a = 70 Divide both sides by 5 a = 70 / 5 = 14 The numbers : 14, 15, 16, 17...
*July 19, 2016*

**math**

g = the greater angle s = the smaller angle = g / 2 The sum of the angles in a triangle is 180 ° 60 ° + g + s = 180 ° 60 ° + g / 2 + g = 180 ° 60 ° + g / 2 + 2 g / 2 = 180 ° 60 ° + 3 g / 2 = 180 ° Subtract 60 ° to both sides 3 g / 2 = ...
*July 19, 2016*

**math**

cos ^ 2 A = 1 - sin ^ 2 A cos ^ 6 A + sin ^ 6 A = ( 1 - sin ^ 2 A ) ^ 3 + ( sin ^ 2 A ) ^ 3 = _________________________________Remark : ( a - b ) ^ 3 = a ^ 3 - 3 a ^ 2 b + 3 a b ^ 2 - b ^ 3 In case ( 1 - sin ^ 2 A ) ^ 3 a = 1, b = sin ^ 2 A so : ...
*July 18, 2016*

**math**

S = number of students g = number of girls b = number of boys b = g + 17 S = g + b S = g + g + 17 S = 2 g + 17 g = 4 / 9 S so : S = 2 * ( 4 / 9 ) S + 17 S = ( 8 / 9 ) S + 17 Subtract ( 8 / 9 ) S to both sides S - ( 8 / 9 ) S = ( 8 / 9 ) S + 17 - ( 8 / 9 ) S ( 9 / 9 ) S - ( 8...
*July 7, 2016*

**Pre-Cal**

Use Trigonometric Identities : sin ( x / 2 ) = + OR - sqroot [ ( 1 - cos x ) / 2 ] cos ( x / 2 ) = + OR - sqroot [ ( 1 + cos x ) / 2 ] 0° < x < 90° meen x lies in Quadrant I In Quadrant I sin x and cos x are positive so : sin ( x / 2 ) = sqroot [ ( 1 - cos x ) / ...
*July 7, 2016*

**math**

30 = 8 * sqroot ( h - 40 ) Divide both sides by 8 30 / 8 = sqroot ( h - 40 ) 2 * 15 / ( 2 * 4 ) = sqroot ( h - 40 ) 15 / 4 = sqroot ( h - 40 ) Raise both sides to the power of two : ( 15 / 4 ) ^ 2 = h - 40 225 / 16 = h - 40 Add 40 to both sides 225 / 16 + 40 = h - 40 + 40 225...
*July 6, 2016*

**math**

3 x / 4 - 16 = 44 Add 16 to both sides 3 x / 4 - 16 + 16 = 44 + 16 3 x / 4 = 60 Multiply both sides by 4 3 x = 240 Divide both sides by 3 x = 240 / 3 x = 80 Proof : 3 * 80 / 4 - 16 = 240 / 4 - 16 = 60 - 16 = 44
*July 2, 2016*

**Mathematics**

P ( x ) = x ^ 3 + 2 x ^ 2 - 11 x - 12 This is a polynomial of degree 3. To find zeros for polynomials of degree 3 or higher we use Rational root test. The Rational Root Theorem tells you that if the polynomial has a rational zero then it must be a fraction p / q, where p is a ...
*July 2, 2016*

**math**

W / L = 60 / 80 = 20 * 3 / 20 * 4 = 3 / 4
*July 2, 2016*

**Math**

A = Ama's ages K = Karla's ages D = Daniel's ages Ama is 3 years older than Karla this mean : A = K + 3 Daniel is 2 years older than Ama this mean : D = A + 2 The sum of their ages is 32 this mean : A + K + D = 32 Now you have 3 equatios : A = K + 3 D = A + 2 A + K...
*June 25, 2016*

**Math**

x = 10% = 10 / 100 = 0.1 10% acid solution of 40 mL = 0.1 * 40 mL = 4 mL of acid Volume of new acid solution = 40 mL + x where x = volume of added wather 4 mL represent 4 % 4 % = 4 / 100 = 0.04 Now 4 mL of acid / new volume = 4 % =0.04 4 mL / ( 40 mL + x ) = 0.04 In ...
*June 24, 2016*

**Math**

4 3 / 5 = 4 + 3 / 5 = 4 * 5 / 5 + 3 / 5 = 20 / 5 + 3 / 5 = 23 / 5 ( 2 / 3 ) / 4 3 / 5 = ( 2 / 3 ) / ( 23 / 5 ) = 2 * 5 / ( 3 * 23 ) = 10 / 69 pounds
*June 12, 2016*

**math**

3 ( x - 2 ) ^ 2 - 12 = 0 Divide both sides by 3 3 ( x - 2 ) ^ 2 / 3 - 12 / 3 = 0 / 3 ( x - 2 ) ^ 2 - 4 = 0 Add 4 to both sides ( x - 2 ) ^ 2 - 4 + 4 = 0 + 4 ( x - 2 ) ^ 2 = 4 Take square root of both sides x - 2 = + OR - sqroot ( 4 ) x - 2 = + OR - 2 1 solution : x - 2 = - 2 ...
*June 12, 2016*

**algebra**

Yes. ( x + c ) ^ 2 = x ^ 2 + 2 * x * c + c ^ 2 In this case : 2 x c = 14 x Divide both sides bny 2 x 2 x c / 2 x = 14 x / 2 x c = 7 So : ( x + c ) ^ 2 = x ^ 2 + 2 * x * c + c ^ 2 ( x + 7 ) ^ 2 = x ^ 2 + 2 x * 7 + 7 ^ 2 = x ^ 2 + 14 x + 49
*June 1, 2016*

**algebra 1**

x ^ 8 * 2 y ^ 10 * 5 x ^ 5 = 2 * 5 * x ^ 8 * x ^ 5 * y ^ 10 = 10 x ^ ( 8 + 5 ) * y ^ 10 = 10 x ^ 13 y ^ 10
*June 1, 2016*

**Algebra**

f ( x ) = - x ^ 2 + 5 x + 4 f ( 3 ) = - 3 ^ 2 + 5 * 3 + 4 = - 9 + 15 + 4 = 10 f ( 5 ) = - 5 ^ 2 + 5 * 5 + 4 = - 25 + 25 + 4 = 4 The average rate of change : [ f ( 5 ) - f ( 3 ) ] / ( 5 - 3 ) = ( 10 - 4 ) / ( 5 - 3 ) = 6 / 2 = 3 Answer A
*May 24, 2016*

**Maths (Need Help)**

If y^2-1/4y=0 mean : y ^ 2 - ( 1 / 4 ) y = 0 then : Write y ^ 2 like : 4 y ^ 2 / 4 Now : 4 y ^ 2 / 4 - ( 1 / 4 ) y = 0 ( 1 / 4 ) 4 y - ( 1 / 4 ) y = 0 ( 1 / 4 ) ( 4 y ^ 2 - y ) = 0 ( 1 / 4 ) y ( 4 y - 1 ) = 0 Now you must solwe two equations : ( 1 / 4 ) y = 0 and 4 y - 1 = 0...
*May 24, 2016*

**math**

Go on : calc101.c o m When page be open click option : derivative then in rectangle Take the derivative of type : sin[cos[x^2]] and click option : DO IT You will see solution step by step.
*May 24, 2016*

**Math**

d = Diameter P = Perimeter P = d * pi = 14 * pi 4 P = 4 * 14 * pi = 56 pi = 56 * 3.14159 = 175.92904 in approx. 176 in
*May 24, 2016*

**Math**

Now Rony is 16 years old Sister is 16 / 4 = 4 years old After x years Rony will be 16 + x yeras old Sister will be 4 + x years old Now you must solve equation : ( 16 + x ) / ( 4 + x ) = 2 Multiply both sides by 4 + x 16 + x = 2 ( 4 + x ) 16 + x = 8 + 2 x Subtract 8 to both ...
*May 24, 2016*

**Algebra**

c = children a = adults 2200 people enter the zoo mean : c + a = 2200 $4,550.00 is collected mean : 1.5 c + 4 a = 4550 Now you must solve system: c + a = 2200 1.5 c + 4 a = 4550 c + a = 2200 Subtract c to both sides c + a - c = 2200 - c a = 2200 - c 1.5 c + 4 a = 4550 1.5 c + ...
*May 24, 2016*

**Algebra**

x = 70% alcohol solution y = 30% alcohol solution 120 L of a 45% solution have : 120 * 0.45 = 54 L alcohol Now you must solve system : 0.7 x + 0.3 y = 54 x + y = 120 The solutions are : x = 45 L , y = 75 L Proof : 0.7 * 45 + 0.3 * 75 = 31.5 + 22.5 = 54 L x + y = 45 + 75 = 120 L
*May 20, 2016*

**5th grade math**

1 ft = 12 in 60 / 12 = 5 ft
*May 18, 2016*

**Algebra**

Correct answer. ( a + b ) ^ 2 = a ^ 2 + 2 a b + b ^ 2 In this case : a = 1 2 a b = 9 2 * 1 * b = 9 2 b = 9 Divide both sides by 2 b = 9 / 2 c = b ^ 2 = ( 9 / 2 ) ^ 2 = 81 / 4 ( x + 9 / 2 ) ^ 2 = x ^ 2 + 9 x + ( 81 / 4 )
*May 13, 2016*

**Maths**

y = the width L = the length A = the area of original rectangle A = y * L = 140 y * L = 140 Divide both sides by y L = 140 / y New area : ( y - 2 ) ( L + 3 ) = 136 ( y - 2 ) ( 140 / y + 3 ) = 136 y * 140 / y - 2 * 140 / y + 3 * y - 3 * 2 = 136 140 - 280 / y + 3 y - 6 = 136 - ...
*May 12, 2016*

**Algebra**

( 1 / 2 ) ( k - 5 ) = 3 Multiply both sides by 2 k - 5 = 6 Add 5 to both sides k - 5 + 5 = 6 + 5 k = 11 Proof : ( 1 / 2 ) ( k - 5 ) = ( 1 / 2 ) ( 11 - 5 ) = 6 / 2 = 3
*May 10, 2016*

**College Math**

x = 3 -inch bolts y = 4 -inch bolts James bought 24 bolts. This mean x + y = 24 36 cents = $ 0.36 42 cents = $ 0.42 Total price = $ 9 This mean : 0.36 x + 0.42 y = 9 Now you must solve system : x + y = 24 0.36 x + 0.42 y = 9 Try.
*May 6, 2016*

**Math**

17 85 : 51 = 17 * 5 : ( 17 * 3 ) = 5 : 3
*May 5, 2016*

**Geometry (Help)**

12 cm / 4 cm = 3 16 cm / 4 cm = 4 8 cm / 4 cm = 2 3 * 4 * 2 = 24 balls
*May 4, 2016*

**Algebra 1**

90 gallons of a 23% salt water = 90 * 23 / 100 = 2070 /100 = 20.7 gallons of salt. x = quantity of salt wather y = quantity of fresh wather Fresh wather have 0 % salt. This mean all salt come on 30 % salt wather. Quantity of salt in 30 % salt wather = 0.3 x 0.3 x = 20.7 Divide...
*May 4, 2016*

**MATH HELP ASAP**

In a Geometric Sequence each term is found by multiplying the previous term by a constant. In this case constant = 0.5 Geometric Sequence
*May 4, 2016*

**MATH HELP ASAP**

1.6 * 0.5 = 0.8 0.8 * 0.5 = 0.4 0.4 * 0.5 = 0.2 What do you think that is?
*May 4, 2016*

**math**

1 3/8 = 1 + 3 / 8 = 8 / 8 + 3 / 8 = 11 / 8 ( 1 3/8 ) / ( 5 / 8 ) = ( 11 / 8 ) / ( 5 / 8 ) = ( 8 * 11 ) / ( 8 * 5 ) = 11 / 5 = 10 / 5 + 1 / 5 = 2 + 1 / 5 = 2 1/5 = 2.2
*May 4, 2016*

**MATH HELP ASAP**

If you think on 4,8,12,16,... then : an = 4 n a20 = 4 *20 = 80
*May 4, 2016*

**MATH HELP ASAP**

Which expression?
*May 4, 2016*

**algebra**

4 * 1 = 4 4 * 2 = 8 4 * 3 = 12 4 * 4 = 16 etc. a. 4n
*May 4, 2016*

**alegbra help asap**

2n + 3 2 * 1 + 3 = 2 + 3 = 5 2 * 2 + 3 = 4 + 3 = 7 2 * 3 + 3 = 6 + 3 = 9 2 * 4 + 3 = 8 + 3 = 11 5 , 7 , 9 , 11 Answer c.
*May 4, 2016*

**PLEASE HELP ASAP ALGEBRA**

In an Arithmetic Sequence the difference between one term and the next is a constant, so : 3 - 4.5 = - 1.5 4.5 - 6 = - 1.5 6 - 7.5 = - 1.5 The difference is a constant, so : a. arithmetic sequence
*May 4, 2016*

**algebra**

The area of a triangle is always half the product of the base and height. In this case the base : b = c + 2 A = b * h / 2 A = ( c + 2 ) * h / 2 The area is ( 2 c ^ 3 + 16 ) so: 2 c ^ 3 + 16 = ( c + 2 ) * h / 2 Multiply both sides by 2 4 c ^ 3 + 32 = ( c + 2 ) * h Divide both ...
*May 4, 2016*

**Math**

3 x ^ 2 = 0 Divide both sides by 3 3 x ^ 2 / 3 = 0 / 3 x ^ 2 = 0 x = sqroot ( 0 ) = 0
*May 3, 2016*

**Math**

a = apples cost o = orange cost 70 cents = 0.7 $ An orange cost 70 cents less than an apple. This mean : o = a - 0.7 $ Total cost = 41.6 $ 8 a * 10 o = 41.6 8 a + 10 ( a - 0.7 ) = 41.6 8 a + 10 a - 7 = 41.6 18 a - 7 = 41.6 Add 7 to both sides 18 a - 7 + 7 = 41.6 + 7 18 a = 48....
*May 3, 2016*

**algebra 2**

2 x + 6 y = 16 Multiply both sides by 2 4 x + 5 y = 11 - 4 x + 12 y = 32 ________________ 4 x - 4 x + 5 y - 12 y = 11 - 32 - 7 y = - 21 Divide both sides by - 7 y = - 21 / - 7 y = 3 Replace value of y in equation : 4 x + 12 y = 32 4 x + 12 * 3 = 32 4 x + 36 = 32 Subtract 36 to...
*May 3, 2016*

**Maths**

x = a number x + x / 2 = 6 2 x / 2 + x / 2 = 6 3 x / 2 = 6 Multiply both sides by 2 3 x = 12 Divide both sides by 3 x = 12 / 3 = 4 Proof ; 4 / 2 + 4 = 2 + 4 = 6
*April 26, 2016*

**math**

p1 = paper 1 p2 = paper 2 p3 = paper 3 p4 = paper 4 ( a ) The mean of the first three papers Jenny has sat is 72%. ( p1 + p2 + p3 ) / 3 = 72 % Multiply both sides by 3 p1 + p2 + p3 = 72 % * 3 = p1 + p2 + p3 = 216 % After 4 papres mean is : ( p1 + p2 + p3 + p4 ) / 4 If she ...
*April 26, 2016*

**Algebra I DONT KNOW HOW TO DO 3 VARIABLES**

x + y + 5 z = 2 4 x - 3 y + 5 z = 3 3 x - 2 y + 5 z = 1 All three equations contain member 5 z Equation ( 1 ) x + y + 5 z = 2 Subtract ( x + y ) to both sides x + y + 5 z - ( x + y ) = 2 -( x + y ) 5 z = 2 - x - y Equation ( 2 ) 4 x - 3 y + 5 z = 3 Subtract ( 4 x - 3 y ) to ...
*April 25, 2016*

**Ratios!!!!**

Remark : 1 * ( x - 3 ) : ( 3 x - 2 ) = ( x - 3 ) : ( 3 x - 2 ) 4 / 4 = 1 so : ( 4 / 4 ) * ( x - 3 ) : ( 3 x - 2 ) 4 * ( x - 3 ) : [ 4 * ( 3 x - 2 ) ] = ( 4 x - 12 ) : ( 12 x - 8 ) Question 10 Answers B and D
*April 21, 2016*

**Ratios!!!!**

8. A = Abby's part I = Ingrid's part J = John's part There are sixty three candies in the bag. This mean: A + I + J = 63 A / I / J = 2 / 3 / 4 This mean : A / I = 2 / 3 I / J = 3 / 4 so: A / I = 2 / 3 Multiply both sides by I A = 2 I / 3 A = ( 2 / 3 ) I I / J = 3...
*April 21, 2016*

**Math**

B = Bill's money S = Sammy's money M = Mary's money J = James's money Sammy has 15 $ more than Billy. S = B + 15 Mary has twice as much as Sammy. M = 2 S = 2 ( B + 15 ) = 2 B + 2 * 15 = 2 B + 30 James has 5 $ less than Mary. J = M - 5 = 2 B + 30 - 5 = 2 B + 25 ...
*April 18, 2016*

**Math**

a = First number b = Second number The difference between two numbers is 6. This mean : a - b = 6 Their product is 2016. This mean : a * b = 2016 Now : a - b = 6 Add b to both sides a - b + b = 6 + b a = 6 + b a = b + 6 Replace this value in expression : a * b = 2016 ( b + 6...
*April 18, 2016*

**math**

cot x = cos x / sin x sec x = 1 / cos x cot x * sec x = ( cos x / sin x ) * ( 1 / cos x ) = 1 / sin x = csc x
*April 18, 2016*

**Maths**

a = the smaller number b = the larger number The product of two natural numbers is 18. This mean : a * b = 18 If one is added to four times the smaller number this is equal to the larger number. This mean : 1 + 4 a = b So : b = 1 + 4 a Replace this value in expression : a * b...
*April 18, 2016*

**Math Trig**

Correct answer but you also can write : cos ( 2 u ) = cos ^ 2 ( u ) - sin ^ 2 u In this case : sin ( u ) = 5 / 13 sin ^ 2 ( u ) = ( 5 / 13 ) ^ 2 = 25 / 169 cos ^ 2 ( u ) = 1 - sin ^ 2 ( u ) = 1 - 25 / 169 = 169 / 169 - 25 / 169 = 144 / 169 cos ( 2 u ) = cos ^ 2 ( u ) - sin ^ 2...
*April 14, 2016*

**Math**

Correct answer becouse : ( 0.0015 / 0.45 ) * 100 % = 0.003333 * 100 % = 0.3333 %
*April 14, 2016*

**Math**

sin theta = + OR - sqroot ( 1 - cos ^ 2 theta ) tan theta = sin theta / cos theta tan theta = + OR - sqroot ( 1 - cos ^ 2 theta ) / cos theta In Quadrant IV tangent are negative so : tan theta = - sqroot ( 1 - cos ^ 2 theata ) / cos theta
*April 14, 2016*

**math**

sqrt ( 4 / 32 ) = sqrt [ 4 / ( 4 * 8 ) ] = sqrt ( 1 / 8 ) = sqrt [ 1 / ( 4 * 2 ) ] = sqrt ( 1 ) / [ sqrt ( 4 ) * sqrt ( 2 ) ] = 1 / 2 sqrt ( 2 ) 2 pi sqrt ( 4 / 32 ) = 2 pi * 1 / 2 sqrt ( 2 ) = pi / sqrt ( 2 ) = _________________________________ Remark: sqrt ( 2 ) = 2 ^ ( 1 / ...
*April 14, 2016*

**math**

In quadratic equation: a x ^ 2 + b x + c value D = b ^ 2 - 4ac is called the discriminant. When Discriminant is zero we get just one real solution. p x ^ 2 - 12 x + 4 = 0 In this case : a = p , b = - 12 , c = 4 D = b ^ 2 - 4 a c = ( - 12 ) ^ 2 - 4 * p * 4 = 144 - 16 p = 0 Add ...
*April 14, 2016*

**problem solving**

S = Susan's age R = Ritas's age Susan is 4 years older than her sister Rita. This mean : S = R + 4 Seven years ago Susan was ( S - 7 ) yrs old, and Rita was ( R - 7 ) yrs old. Seven years ago, Susan was twice as old as Rita. This mean : ( S - 7 ) / ( R - 7 ) = 2 ...
*April 10, 2016*

**Trigonometrt**

a. 810 ° = 720 ° + 90 ° = 2 * 360 ° + 90 ° So : sin ( 810 ° - theta ) = sin ( 90 ° - theta ) sin ( A - B ) = sin A * cos B - cos A * sin B In this case A = 90 ° , B = theta. sin 90 ° = 1 cos 90 ° = 0 sin ( 90 ° - theta ) = sin 90 &...
*April 9, 2016*

**Algebra**

x + 2 y = 10 Subtract x to both sides x + 2 y - x = 10 - x 2 y = 10 - x Divide both sides by 2 2 y / 2 = 10 / 2 - x / 2 y = 5 - x / 2 x ^ 2 + y ^ 2 = 25 x ^ 2 + ( 5 - x / 2 ) ^ 2 = 25 ________________________________ Remark: ( a - b ) ^ 2 = a ^ 2 - 2 * a * b + b ^ 2 ...
*April 6, 2016*

**math**

( - 8 ) * ( - 7 ) = ( - 1 * 8 ) * ( - 1 * 7 ) = ( - 1 ) * ( - 1 ) * 8 * 7 = 1 * 8 * 7 = 1 * 56 = 56
*April 5, 2016*

**Algebra 1**

a = larger number b = smaller number One third the sum of two numbers is 10. This mean: ( a + b ) / 3 = 10 Multiply both sides by 3 a + b = 30 Half the difference is 14. This mean: ( a - b ) / 2 = 14 Multiply both sides by 2 a - b = 28 Add b to both sides a - b + b = 28 + b a...
*April 5, 2016*

**Algebra**

4 x - 6 y - 3 = 7 x + 2 y - 4 Subtract 4 x to both sides 4 x - 6 y - 3 - 4 x = 7 x + 2 y - 4 - 4 x - 6 y - 3 = 3 x + 2 y - 4 Add 3 to both sides - 6 y - 3 + 3 = 3 x + 2 y - 4 + 3 - 6 y = 3 x + 2 y - 1 Subtract 2 y to both sides - 6 y - 2 y = 3 x + 2 y - 1 - 2 y - 8 y = 3 x - 1...
*April 5, 2016*

**maths**

( 14 / 40 ) * 100 % = 0.35 * 100 % = 35 %
*April 5, 2016*

**Math**

1 ft = 12 in 2 ft = 24 in r = 24 in = 2 ft The volume of a ball: V = ( 4 / 3 ) * pi * r ^ 3 = ( 4 * pi / 3 ) * 2 ^ 3 = ( 4 * 3.1416 / 3 ) * 2 ^ 3 = ( 12.5664 / 3 ) * 2 ^ 3 = 4.1888 * 2 ^ 3 = 4.1888 * 8 = = 33.5104 ft ^ 3
*April 5, 2016*

**math**

3 / 27 = 3 / ( 3 * 9 ) = 1 / 9 3 / 27 = 10 / x 1 / 9 = 10 / x Multiply both sides by 9 1 = 90 / x Multiply both sides by x x = 90 min OR x = ( 10 miles / 3 miles ) * 27 min = ( 10 / 3 ) * 27 min = 270 min / 3 = 90 min
*April 5, 2016*

**Social studies**

Ms.Sue Iam from Sarajevo, Bosnia and Herzegovina, former Yugoslavia citizen. YUGOSLAVIA WAS NEVER HAD SOVIET RULE. It was very different from the socialism of the Soviet.
*March 30, 2016*

**pr calc 11**

The numbers are: 8 an - 5 becouse: 8 * ( - 5 ) = - 40 and 8 - 5 = 3 x ^ 2 + 3 x - 40 = ( x + 8 ) ( x - 5 )
*March 30, 2016*

**pr calc 11**

( a + b ) ^ 2 = a ^ 2 + 2 a b + b ^ 2 so: ( x + 2 ) ^ 2 = x ^ 2 + 2 x * 2 + 2 ^ 2 = x ^ 2 + 4 x + 4 ( x + 2 ) ^ 2 - ( x + 2 ) - 42 = x ^ 2 + 4 x + 4 - x - 2 - 42 = x ^ 2 + 4 x + 4 - x - 44 = x ^ 2 + 4 x - x + 4 - 44 = x ^ 2 + 3 x - 40 Find two numbers whose product is - 40 and...
*March 30, 2016*

**Math**

Parabola - 5 t ^ 2 - 25 t is concave downward. That's why you get negative time. You can switch - 5 to 5. If you want to see graph go on: w o l f r a m a l p h a . c o m When page be open in rectangle type: - 5 t ^ 2 - 25 t , t = 0 to - 5 and click option: = You wil see ...
*March 29, 2016*

**math**

x = 0.6969... 100 x = 0.6969... * 100 = 69.6969... 100 x - x = 99 x = 69.6969... - 0.6969... = 69 99 x = 69 3 * 33 x = 3 * 23 Divide both sides by 3 33 x = 23 Divide both sides by 33 x = 23 / 33 0.6969... = 23 / 33
*March 24, 2016*

**math**

1 / 2 (14 x - 2 ) - 1 / 4 ( - 4 x - 24 ) = 14 x / 2 - 2 / 2 - ( - 4 x / 4 ) - ( - 24 / 4 ) = 14 x / 2 - 2 / 2 + ( 4 x / 4 ) + ( 24 / 4 ) = 7 x - 1 + x + 6 = 8 x + 5
*March 24, 2016*

**Math**

In google type: integration by parts online emathelp When you see list of results cilck on: Integral (Antiderivative) Calculator with Steps - eMathHelp When page be open in rectangle type: e^(3x) sin (2x) then clic option: CALCULATE You wil see solution step-by-step.
*March 24, 2016*

**algebra i**

You can square rooted only expresiion between brackets, not single number.
*March 21, 2016*

**algebra i**

( x - 4 ) ^ 2 = 625 Take square root to both sides + OR - ( x - 4 ) = 25 1 solution: x - 4 = 25 Add 4 to both sides x - 4 + 4 = 25 + 4 x = 29 2 solution: - ( x - 4 ) = 25 - x + 4 = 25 Subtract 4 to both sides - x + 4 - 4 = 25 - 4 - x = 21 Multiply both sides by - 1 x = - 21 ...
*March 21, 2016*

**Math haha**

7 / 2 = ( 7 / 2 ) * ( 3 / 3 ) = 21 / 6 ( 7 / 2 + 5 / 6 ) ^ 2 - ( 7 / 2 - 5 / 6 ) ^ 2 = ( 21 / 6 + 5 / 6 ) ^ 2 - ( 21 / 6 - 5 / 6 ) ^ 2 = ( 26 / 6 ) ^ 2 - ( 16 / 6 ) ^ 2 = 676 / 36 - 256 / 36 = ( 676 - 256 ) / 36 = 420 / 36 = ( 12 * 35 ) / ( 12 * 3 ) = 35 / 3
*March 20, 2016*

**Math-Measure's & area**

1. A = B * H = 82 * 16.6 = 1,361.2 2. 0.123333.... is a rational number becouse : 0.123333... = 37 / 300
*March 17, 2016*

**Math**

Rectangular pyramid
*March 17, 2016*

**algebra**

OR x + 9 y = 77 Multiply both sides by 7 7 * x + 9 y * 7 = 77 * 7 7 x + 63 y = 539 - 7 x - y = 27 _______________ 7 x - 7 x + 63 y - ( - y ) = 539 - 27 0 + 63 y + y = 512 64 y = 512 y = 512 / 64 = 8 x + 9 y = 77 x + 9 * 8 = 77 x + 72 = 77 Subtract 72 to both sides x + 72 - 72...
*March 13, 2016*

**algebra**

7 x - y = 27 Divide both sides by 7 7 x / 7 - y / 7 = 27 / 7 x - y / 7 = 27 / 7 x + 9 y = 77 x + 9 y * 7 / 7 = 77 * 7 / 7 x + 63 y / 7 = 539 / 7 Subtract x - y / 7 = 27 / 7 from equation x + 63 y / 7 = 539 / 7 x + 63 y / 7 = 539 / 7 - x - y / 7 = 27 / 7 ...
*March 13, 2016*

**Math**

Numbers 1 ÷ 9 are one digits numbers. Numbers 10 ÷ 30 are two digits numbers. Obviously Eric will write 9 one digits numbers and 21 two digits numbers. 9 * 1 + 21 * 2 = 9 + 42 = 51 digits
*March 9, 2016*

**Math**

55 = 11 * 5
*March 8, 2016*

**Math**

You can write original number as : x = 10 a + b Reverse number you can write as : y = 10 b + a x + y = 10 a + b + 10 b + a = 11 a + 11 b = 11 ( a + b ) Example : Original number: x = 23 a = 2 , b = 3 x = 10 a + b = 10 * 2 + 3 = 20 + 3 = 23 Reverse number: y = 10 b + a = 10 * 3...
*March 8, 2016*

**database**

Find answer on wikipedia.
*March 8, 2016*

**maths**

x = 0.27272727... 100 x = 100 * 0.27272727... 100 x = 27.27272727... 100 x - x = 99 x = 27.27272727... - 0.27272727... = 27 99 x = 27 9 * 11 x = 9 * 3 Divide both sides by 9 11 x = 3 Divide both sides by 11 x = 3 / 11
*March 7, 2016*

**Math**

A golden rectangle is a rectangle whose side lengths are in the golden ratio: phi = 1 / [ ( 1 + sqroot 5 ) / 2 ] W = L * phi W = 12 * 1 / [ ( 1 + sqroot 5 ) / 2 ] = 12 * 2 / ( 1 + sqroot 5 ) = 24 / ( 1 + sqroot 5 ) = 24 / ( 1 + 2.236068 ) = 24 / 3.236068 = 7.416408 ft W = 7.4 ...
*March 7, 2016*

**Math**

x ^ 2 + 10 = 7 x Subtract 7 x to both sides x ^ 2 + 10 - 7 x = 7 x - 7 x x ^ 2 - 7 x + 10 = 0 Now you must solve this quadratic equation. The solutions are : x = 2 and x = 5 Proof : 2 ^ 2 + 10 = 4 + 10 = 14 = 7 * 2 5 ^ 2 + 10 = 25 + 10 = 35 = 7 * 5
*March 6, 2016*

**math**

x1 = score math = 65 x2 = score arts = 86 x3 = score science = 84 x4 = score social studies = 78 x5 = score grammar average = ( x1 + x2 + x3 + x4 + x5 ) / 5 = 80 ( 65 + 86 + 84 + 78 + x5 ) / 5 = 80 ( 313 + x5 ) / 5 = 80 Multiply both sides by 5 313 + x5 = 80 * 5 313 + x5 = 400...
*March 5, 2016*