Monday

January 16, 2017
Total # Posts: 37,283

**Math**

no! when adding fractions with the same denominator like we have here, you add the numerators only and keep the denominator. 21/2 plus 21/2 plus 21/2 = 63/2 and (63/2)(44/3) = 2772/6 = 462 In my actual calculation, I would have cancelled the 3 into the 63 --> 21 and the 2 ...

*September 8, 2016*

**Math**

That would work, since the width is apparently the same for all three, so is the length. total area = (21/2)(44/3) + (21/2)(44/3) + (21/3)(44/3) = 462 or = (44/3)(21/2 + 21/2 + 21/2) <---- your way = 462 or, even simpler = 3(21/2)(44/3) = 462

*September 8, 2016*

**Math**

looks like just 3x3x3 or 27 to me

*September 8, 2016*

**Math**

it said "to use 2/5 of the paint" the English word "of" usually indicates that you would be multiplying. eg. give me 1/2 of $6.00 so (1/2)(6.00) = $3.00 Very often, creating a simpler problem with easy numbers let's you get the answer by simple common ...

*September 8, 2016*

**Math**

correct

*September 8, 2016*

**Math**

did you mean that the larger root is x = 5 ? (x-5) would be one of the factors. then if f(x) = x^2 - 5x+ k f(5) = 25 - 25 + k = k for x=5, f(5) must be zero, so k = 0 check: you would have: x^2 - 5x = 0 x(x-5) = 0 roots are 0 and 5, and sure enough 5 is the larger.

*September 8, 2016*

**Math**

Wow, first of all , I think you meant: (√6+√11) * (√3+√3+√11) * (√3+√6+√3+√11) * (√3-√6+√3+√11) Did you really mean for that to be multiplied? Very tedious and long which I don't feel like doing...

*September 8, 2016*

**@ Andarah - maths**

It was sheer coincidence that you ended up with the correct answer. Where did you get (5-3) from ?? correct solution steps: 3x-5 = 10 3x = 10+5 3x = 15 x = 15/3 x = 5

*September 8, 2016*

**maths**

3x-5 = 10 solve for x

*September 8, 2016*

**math**

actual number of oranges ---- x number of fresh oranges = x-15 number of apples = x+40 x + x+40 = 568 2x = 528 x = 264 number of oranges = 264 number of apples = 304 number of fresh oranges = 264-15 = 249 apples - fresh oranges = 304-249 = 55

*September 8, 2016*

**Algebra 2**

just plug in 3 wherever you see an x p(3) = 2(3^3) + 8(3^2) - 7(3) = 54 + 72 - 21 = ...

*September 8, 2016*

**math**

Did you make a sketch? on mine, I labeled the original point A, and the closer point B. Top of the church P, bottom of church Q AB = 30, angle A = 35°, angle PBQ = 55° in triangle PAB, angle PBA = 125°, then angle APB = 20° by the sine law: BP/sin35 = 30/sin20 ...

*September 8, 2016*

**Algebra II**

Here is a cute little video from the KhanAcademy to show the basic method. It will depend on how you were taught whether you divide by 7 or by 6. You will have to check your notes or your textbook https://www.khanacademy.org/math/statistics-probability/displaying-describing-...

*September 7, 2016*

**Math**

notice that the difference in your inputs in 1, while the difference in your outputs is 3 so you have a slope of 3 let's start with y = 3x + b when x = 2, y = 2 so 2 = 3(2) + b -4 = b f(x) = 3x - 4 check with a few values.

*September 7, 2016*

**Algebra**

#4, oh dear!!! (2x-3)(4x+3) = 8x^2 + 6x - 12x - 9 = 8x^2 - 6x - 9 #5 , same as #4 (4x-3)(4x+3) = 16x^2 + 12x - 12x - 9 = 16x^2 - 9 <--- called the difference of squares make sure you are familiar with FOIL, F : multiply the firsts O : multiply the "outers" I : ...

*September 7, 2016*

**Algebra**

#2: (4h^3+3h+1)-(-5h^3+6h-2) think of it as (4h^3+3h+1)-1(-5h^3+6h-2) = 4h^3 + 3h + 1 + 5h^2 - 6h + 2 = 9h^2 -3h + 3 #3 5k (3-4k) = 15k - 20k^2 by the distributive property

*September 7, 2016*

**math**

c + 2s = 10 3c + 2s = 18 subtract them: 2c = 8 c = 4 then 4+2s=10 s = 3 poor way to type it, at first I though the chalk and 2 staples cost $10.30

*September 7, 2016*

**No --- Algebra 1**

number of boys --- 7x number of girls --- 2x 2x = 48 x = 24 number of boys = 7x = 7(24) = 168 there are 168 boys. your ratio equation should have been 7/2 = x/48 2x = 336 x = 168

*September 7, 2016*

**Algebra**

Assuming your figure is a rectangle ... perimeter = sum of all 4 sides = 15/6 + 15/6 + 15/6 + 15/6 = 60/6 = 10 Why you would do: 15+ 15+15+15 and divided by 4 is beyond me.

*September 7, 2016*

**Algebra**

g(6) = 6^2 - 5 = 31 f(g(6)) = f(31) = -2(31) - 1 = -63

*September 7, 2016*

**mathematics**

after giveaway: greg has (2/3)x after sale he has (2/3)(2/3)x = (4/9)x (4/9)x=80 x = 180 take over

*September 7, 2016*

**Math**

(x,y) ---> (x-5, y + 11)

*September 7, 2016*

**Math**

390 was the total, so number of adults --- 8x number of kids ----- 5x 8x+5x = 390 13x = 390 x = 30 so 240 adults and 150 kids check: 240+150 = 390 240 : 150 = 24:15 = 8 : 5

*September 7, 2016*

**9th grade algebra**

#1, done well #2, your sketch should look like this http://www.wolframalpha.com/input/?i=plot+f(x)+%3D+-5%2F6x+,+g(x)+%3D+2%2F5x+%2B+4 look at the 2nd graph looks like appr (-3.25, 2.5) to me, so your guess is close your check: f(x): 2.5 =-5/6(-3.1) 2.5 = -2.58 <----- ...

*September 7, 2016*

**Math - vectors**

so you want: (14, - 12) = k(4, t) that is, 14 = 4k and -12 = kt 4k = 14 k = 14/4 = 7/2 then kt = -12 (7/2)t = -12 t = -12(2/7) = -24/7

*September 7, 2016*

**Two bus trvl in opposite direction frm that same rtarting point.if d speed of 1 is twice d speed of d other and de 240km**

Repost your question using the English language.

*September 7, 2016*

**Math**

speed of boat in still water ---- x mph speed of current ---- y mph (1/2)(x+y) = 10 x + y = 20 2(x-y) = 10 x - y = 5 add them 2x = 25 x = 12.5 then y = 7.5 state the conclusion.

*September 7, 2016*

**Alg 1**

so far you have a total of 251 lowest mark needed: (251+x)/4 >84 251+x > 336 x > 85 highest mark needed: (251+x)/4 < 86 251+x < 344 x < 93 possible scores are 86, 87, 88, 89, 90, 91, and 92 Question: why would you NOT want a score highter than 86 ?

*September 7, 2016*

**math**

-2 ( 4x - 3y + 18) = -8x + 6y - 36 , using the distributive property

*September 7, 2016*

**math**

1+2y<23 2y < 22 y < 11

*September 7, 2016*

**Geometry**

To me a two column proof is usually associated with Euclidean Geometry. To use it here in this rather simplistic problem is like using a sledge hammer to drive in a finishing nail ... here is what I would do 7y=8x-14; y=6 then: 42 = 8x - 14 56 = 8x x = 56/8 = 7 There! I have ...

*September 7, 2016*

**math**

5(x + 10) + x 6x + 15 5x + 15 6x + 50 4x – 50 ?? took me a while to realize that you just linked the possible answers together, which of course makes no sense if the question is simplify 5(x + 10) + x I don't understand why you are having problems clearly saying &...

*September 7, 2016*

**Math**

I am looking but can't see the shelf

*September 6, 2016*

**Algebra**

let the number of weeks be w when is 900 - 10w = 500 + 15w solve for w

*September 6, 2016*

**Math**

10×10^4+2.8×10^6 = 100,000 + 2,800,000 = 2,900,000 or 2.9 x 10^6

*September 6, 2016*

**Math**

1. check with your textbook, the rules should be there 2. check with your classroom notes, you must have them written down 3. Google your terms like "properties of negative exponents"

*September 6, 2016*

**math**

Wouldn't the new band have a radius a little larger than the original? I suspect a typo, and will assume it to be larger C = 2πr 40000 = 2πr r = 6366.197723676.. km new circumference = 40000.002 new r = 6366.23676 km difference = 0.00031831 km = .31831 metres or ...

*September 6, 2016*

**math**

let the piece formed into the first square be x cm then the piece formed into the second square is 5-x cm area of first square = (x/4)^2 = x^2/16 area of 2nd square = (5-x)^2/16 4x^2/16 = (5-x)^2/16 4x^2 = 25 - 10x + x^2 3x^2 + 10x - 25 = 0 (3x-5)(x+5) = 0 x = 5/3 or x = -5, ...

*September 6, 2016*

**Math**

Don't tell me they don't teach long division any more ! 54/6.75 = 5400/675 now divide

*September 6, 2016*

**Algebra**

I am going to call the middle number x, then the smaller is x-2, and the larger is x+2 Now just translate the English to Math: the sum of ----> + 5 times the smaller ---> 5(x-2) number a twice the larger ---> 2(x+2) the sum of 5 times the smaller number a twice the ...

*September 6, 2016*

**Fractions**

area of triangle = (1/2)base x height = (1/2)(7/8)(6/5) = 21/40

*September 6, 2016*

**Math**

follow the steps I used here for a similar question. http://www.jiskha.com/display.cgi?id=1473175123

*September 6, 2016*

**Math**

remember when multiplying powers of the same base we add the exponents 5m^4/3(m^1/3*2n^1/8) = 10 m^(4/3) n^(1/8)

*September 6, 2016*

**Math**

number of ones --- x number of twenties --- x-15 number of fives = 37 - x - (x-15) = 52 - 2x x + 5(52-2x) + 20(x-15) = 191 solve for x, then sub back into my definitions.

*September 6, 2016*

**Linear Algebra**

have you learned that any linear vector can be expressed as (rcosØ , rsinØ) where r is the magnitude and Ø is the angle it makes with the horizontal. so vector u = (15cos30°, 15sin30°) = (15√3/2 , 15/2) and vector v = (17cos55, 17sin55) u*v...

*September 6, 2016*

**algebra 1**

your choices were all correct

*September 6, 2016*

**MATH**

You can round off your daily cost when stating it, but you should carry more accuracy when you then multiply it by 7 or 30 e.g. #1 cost per pill = 1740/300 cents or 6 cents cost for 2 pills = 2(5.8) = 11.6 or 12 cents cost per week = 7(11.6) = 81.2 or 82 cents cost per month...

*September 6, 2016*

**algebra 1**

cost = 25 + 14m so if m = 6 cost = 24 + 14(6) = ...

*September 6, 2016*

**algebra 1**

correct

*September 6, 2016*

**math**

areas are proportional to the square of their diameters area of larger circle : area of smaller circle = 4^2 : 6^2 = 16 : 36 = 4 : 9

*September 6, 2016*

**Algebra**

3x^2-3y=12x+9 divide by 3 and re-arrange y = x^2 - 4x - 3 complete the square ... y = x^2 - 4x + 4 - 4 - 3 = (x - 2)^2 - 7 http://www.wolframalpha.com/input/?i=plot+y+%3D+(x+-+2)%5E2+-+7 axis of symmetry: x = 2

*September 6, 2016*

**Math**

amount in the pail --- x ml amount in the tank ---- 8346 - x ml (8346-x) + 314 = 12(x-314) 8660 - x = 12x - 3768 12428 = 13x x = 956 state conclusion with proper units.

*September 6, 2016*

**math**

number of eggs bought --- x number of eggs sold ----- x-20 4(x-20)/(3x) = 1.2 = 6/5 20x - 400 = 18x 2x = 400 x = 200

*September 6, 2016*

**math**

Since the volume is lwh, and we know h = x+1 then the base is lw = (x^3 + 3x^2 + 2x - 5)/(x+1) = (x^2 + 2x) - 5/(x+1) I had expected the division to be exact. Is there a typo?

*September 6, 2016*

**Math**

Make your sketch. let EC = x , FC = y then (1/2)(x)(y) = 3 xy = 6 area of ABCD = 2x(2y) = 4xy = 24

*September 2, 2016*

**pre calc help please!!!!**

after I took care of your typo x --> x ?? , should be x --> c clearly we just have (5 - 7)^2 = 4

*September 2, 2016*

**math help**

find the direction vector using your two points, then pick one of the points and your direction vector, and follow the method I just showed you in your previous post.

*September 2, 2016*

**math help**

1. x = 1 - t y = -8 + 6t z = -3 - 6t 2. (x-5)/3 = (y+2)/6 = (z+4)/8 did you notice the pattern in the two answers ?

*September 2, 2016*

**math**

weight of cooking oil per litre ---- x kg weight of can ---- y kg 8x + y = 42 3x + y = 27 subtract them 5x = 15 x = 3 sub into 3x + y = 27 9 + y = 27 y = 18 the empty can weighs 18 kg check: 8(3) + 18 = 42 3(3) + 18 = 27 my answer is correct

*September 1, 2016*

**Algebra**

ab - cd will be a maximum if ab is as large as possible and cd is as small as possible I will let d = 1 also we are told that c = a -5, so it is close to a for a maximum of ab, a = b, but our numbers are to be different, and remember that c is only 5 less than a. So we know ...

*September 1, 2016*

**ps12**

7[-7p + 5 + 2(p + 1)] = 6p + 1 7[-7p + 5 + 2p + 2)] = 6p + 1 7[-5p +7] = 6p + 1 -35p + 49 = 6p + 1 -41p = -48 p = 48/41

*September 1, 2016*

**Math**

Think of -n as (-1)(n) so it depends on the value of n if n is positive, then -n is negative. if n is negative, then -n is positive e.g. if n = 5 , -n = -5 , the opposite if n = -5, then -n = -(-5) = +5

*September 1, 2016*

**Algebra**

2x + 1 = x - 2 or 10 - √(6 - x) = 2x - 1 or ....

*September 1, 2016*

**Math**

The LCM, (Least Common Multiple) of 6 and 8 is 24 so you need 24/6 or 4 insects and 24/8 or 3 spiders.

*September 1, 2016*

**Math**

Mary's rate = house/2 Gina's rate = house/3 combined rate = house/2 + house/3 = 5house/6 , (just like 1/2 + 1/3 = 5/6) time at combined rate = house/(5house/6) = house(6)/(5house) = 6/5 notice that "house" canceled, we could have used anything, some would ...

*September 1, 2016*

**maths**

check: amount = 25000(1.08)^2 = 29160 you are correct

*September 1, 2016*

**math**

let the number to be added be x then : (3+x)/(1+x) = (6+x)/(3+x) (1+x)(6+x) = (3+x)(3+x) 6 + 7x + x^2 = 9 + 6x + x^2 x = 3 check: the sequence would then be 4,6, and 9 which is a GP with r = 3/2

*September 1, 2016*

**math**

I assume we are using compound interest. i = .02/12 = .001666... P(1 - 1.001666..^-60)/.001666... = 2000000 I get P = $35055.52 check my arithmetic

*September 1, 2016*

**Math problem soving**

so you are just adding 6 + 12 + 24 + 48 + ... until you get 300 This is the sum of a geometric series with a = 6, and r = 2 sum(n) = a(r^n -1)/(r-1) 300 = 6(2^n -1)/(2-1) 50 = 2^n - 1 2^n = 51 since n has to be a whole number, we can just take a stab at it 2^5 = 32 2^6 = 64 , ...

*September 1, 2016*

**algebriac expression**

second account = d - 3100

*August 31, 2016*

**math**

compare 135/6 with 285/15

*August 31, 2016*

**algebra**

1 cm = 10 mm so L cm = 10L mm be consistent in your spelling, if you use millimetres, then it is also centimetres

*August 31, 2016*

**Math**

7.6×10^6 = 7.6 x 1000000 = ....

*August 31, 2016*

**Boop**

well, you said angle LMN = 6x-20 and angle LMO bisects angle LMN and angle LMO = x+32 so (1/2)(6x-20) = x+32 3x-10 = x+32 2x = 42 x = 21 so angle LMN = 6(21) - 20 = 106 check: then angle LMO = 21+32 = 53 , which is half of 106

*August 31, 2016*

**math**

look at http://www.jiskha.com/display.cgi?id=1472551803 Make any changes necessary. Also consider Steve's method if you have learned about determinants.

*August 31, 2016*

**reiny please help me**

when the tangent line is horizontal, the slope must be zero. But the slope is equal to the derivative, so .... f(x) = 2x^3 + 6x f ' (x) = 6x^2 + 6 then 6x^2 + 6 = 0 6x^2 = -6 x^2 = -1 , good luck on that Since our equation has not real solution, there is no point at which ...

*August 31, 2016*

**math homework**

do we have y = √(x+8) ? I will assume that, if (8,4) lies on it slope = lim ( √(16+h) - 4)/h , as h --->0 multiply top and bottom by (√(16+h) + 4) = lim ( √(16+h) - 4)/h * (√(16+h) + 4)/(√(16+h) + 4) = lim (16 + h - 16)/(h(√(16+h...

*August 31, 2016*

**maths**

Short way: Did you come across this formula yet? distance from a point (a,b,c) to the plane Ax + By + Cz + D = 0 is |Aa + Bb + Cc + D|/√(A^2 + B^2 + C^2) distance = |6 + 10 - 9 + 6|/√(9+4+9) = 13/√22 longer way: parametric equation of perpendicular line from...

*August 31, 2016*

**math**

first equation: m + w = 8000 after discount, price would be .9(8000) = 7200 after VAT, price = 1.1(7200) = 7920 Since I got the final answer without knowing how much the watch or mobile cost, it doesn't matter how much the individual costs. You solution is correct, you can...

*August 31, 2016*

**math**

looks like they played two rounds of the game A's original amount ---- x B's original amount ---- y after first round: A has x+y/4 B has 3y/4 after 2nd round A has x+y/4 - x/3 B has 3y/4 + x/3 ....... You had that, good job, now just have to simplify the equations x+y/...

*August 31, 2016*

**Finance**

So in effect, we want to find the outstanding balance of the mortgage after 8 years. original mortgage = .8(550,000) = 440,000 i = .061/12 = .00508333... P(1 - 1.0050833..^-360)/.00508333.. = 440000 p(165.01792..) = 440000 p = 2666.38 After 8 years, outstanding balance = ...

*August 31, 2016*

**Algebra**

Time taken by the slower train ---- t hrs time taken by faster train --------- t - 1 hrs distance gone by slower train = 40t miles distance gone by faster train = 50(t-1) miles But, when they pass each other, each will have covered the same distance, so 50(t-1) = 40t 50t - 50...

*August 31, 2016*

**algebra**

To answer your question, we would have to know your actual weight, but ... no problem suppose your weight is 130 pounds a) you could lift: 130(1.182 x 10^3) = 153.66 x 10^3 pounds = 153,660 pounds or 1.537 x 10^5 pounds change the solution to match your own weight.

*August 31, 2016*

**math**

Leah, just add them all up, then divide by 44. I am not going to do that simple arithmetic for you. By the way, wouldn't it be spelled metre in Australia ? It is spelled meter only in the US

*August 30, 2016*

**algebra 1**

Use your calculator to find √479 , round to nearest whole number or you know 20x20x = 400 21x21 = 441 22x22 = 484 so what do you think?

*August 30, 2016*

**math**

percent increase = 1000/3000 = 1/3 = ...

*August 30, 2016*

**Calculus**

Make a sketch of the cross-section let the radius be r, let the vertex angle be 2Ø we have a right-angled triangles with angle Ø, opposite is r, and adjacent is 12 tanØ = r/12 12tanØ = r 12 sec^2 Ø (dØ/dt) = dr/dt when r = 6 , ...

*August 30, 2016*

**math homework help**

the major axis lies along the y-axis, so a^2 + 4^2 = 7^2 a^2 = 33 a=√33 x^2/33 + y^2/49 = 1

*August 30, 2016*

**Rainy can you help me with this question?!**

just look at the numbers in the corresponding positions x y 1 9 = 3 5 1 9 so x=3 and y=5

*August 30, 2016*

**math homework help**

If f(x) = 5-2x lim f(x+h) - f(x) / h = lim (5 - 2(x+h) - 5 + 2x)/h = lim (5 - 2x - 2h - 5 + 2x)/h = lim (-2h)/h = -2

*August 30, 2016*

**Maths**

(1/2)x - 1/3 = 4 times 6 , the LCD 3x - 2 = 24 3x = 26 x = 26/3 check: 1/2 of 26/3 = 13/3 difference between 13/3 and 1/3 = 12/3 or 4 we are good here.

*August 30, 2016*

**maths**

I will assume your first equation has a typo, then y = 16-x plug into the 2nd x^2 + (16-x)^2 = 128 2x^2 - 32x +128 = 0 x^2 - 16x + 64 = 0 (x-8)^2 = 0 take over, compare your answer to http://www.wolframalpha.com/input/?i=plot+x%2By%3D16,++x%5E2+%2By%5E2+%3D128

*August 30, 2016*

**math**

Straightforward trig ratio tan Ø = opposite/adjacent tan 40° = height/500 height = 500tan40° = ......

*August 30, 2016*

**calculus**

recall area of parallelogram using vectors u and v = | u X v| go for it, you have u = (-2,1,5) and v = (4,-3,-3)

*August 30, 2016*

**calculus**

if by v * w , you mean v X w , the cross product, then v X w = (5, 8, -1) X (-2, 8, 3) = (32, -13, 56) , I assume you know how to find the cross-product Then u . (v * w) = (5, 9, -6) . (32, -13, 56) = 160 - 117 - 336 = - 293

*August 30, 2016*

**math**

does it look like this ? (9493) ? Are you studying numbers with different bases?

*August 30, 2016*

**math**

What does (94) 93 mean? check your typing.

*August 30, 2016*

**mzumbe**

the difference between 7th and 5th terms is 192 ---> ar^6 - ar^4 = 192 ar^4(r^2 - 1) = 192 ** the difference between 15th and 3rd terms is 48 ---> ar^14 - ar^2 = 48 ar^2(r^12 - 1) = 48 *** divide ** by *** r^2(r^2 - 1)/(r^12 - 1) = 4 **** r^4 - r^2 = 4r^12 - 4 4r^12 - r^...

*August 30, 2016*

**Measurements and applications**

50 mm ----> 4 km 1 mm ------> 4/50 km 75 mm ----> (75)(4/50) km or 6 km ratio = 50 mm : 4 km = 50 mm : 4000000 mm = 1 : 80,000 c) "48squared" km? from your given: (4 km)^2 ---> (50 mm)^ 16 km^2 = 2500 mm^2 1 km^2 = 2500/16 mm^2 48 km^2 = (48)(2500/16) mm^...

*August 30, 2016*

**math**

Use Venn diagrams draw two intersecting circles , one labeled E and the other labeled H within a rectangle. You know the intersection of E and H is 70 and the part outside the two circles is 8 It said 5 failed in H only, so they must have passed E, so they can't be part of...

*August 30, 2016*