Thursday

April 17, 2014

April 17, 2014

Total # Posts: 1,491

**chemistry**

Assuming the gas is ideal, we can use the Ideal Gas Law: PV = nRT where P = pressure in atm V = volum in liters n = number of moles R = universal gas constant = 0.0821 L-atm/mol-K T = temperature in Kelvin We know V, T and of course, R. To convert degree Celsius to Kelvin, we ...

**math**

What you'll do is add 3 and 8 to get the total: 3 + 8 = 11 Now we divide the total number of students by 11: 132/11 = 12 (this is the multiplier for 3 and 8) Therefore, 3 * 12 = 36 students (prefer baseball) 8 * 12 = 96 students (prefer soccer) Hope this helps :3

**math**

What you'll do is add 3 and 8 to get the total: 3 + 8 = 11 Now we divide the total number of students by 11: 132/11 = 12 (this is the multiplier for 3 and 8) Therefore, 3 * 12 = 36 students (prefer baseball) 8 * 12 = 96 students (prefer soccer) Hope this helps :3

**Math check answers plz**

It's 16.67 %. Note that there are six numbers in a dice, and in one roll, the probability of getting a six is 1/6 or 16.67%.

**chemistry**

NiCl2(aq) + 2NaOH(aq) → Ni(OH)2(s) + 2NaCl(aq) First get the number of moles of NaOH. Recall that molarity is moles of solute per liter of solution: M = n / V Getting n, n = MV n = (0.6)(0.025) n = 0.015 mol NaOH To get the mol Ni(OH)2, we multiply the mol of NaOH to the...

**Math**

Yes, it's 16. :)

**Algebra**

25u^2 - 81 This is a difference of two squares. Therefore, the factor is (5u - 9)(5u + 9) hope this helps :3

**Algebra**

20 v^7 u^3 16 x^6 v^4 u^5 GCF of 16 and 20: 4 GCF of v^7 and v^4 : v^4 GCF of u^3 and u^5 : u^3 Thus, the GCF is the product of the three, which is equal to 4 v^4 u^3. hope this helps :3

**math**

To get the slope we use the formula: m = (y2 - y1) / (x2 - x1) where (x1,y1) and (x2,y2) are the points. Substituting, m = (4 - (-1)) / (3 - 2) m = (4 + 1) / 1 m = 5 (a) Note that parallel lines have equal slope. Thus slope of the parallel line is also equal to 5. (b) Note tha...

**ms. sue please help**

Change first the 12 1/2 into improper fraction: 12 1/2 = (12*2 + 1)/2 = 25/2 Then we divide 50 by 25/2 to get the rate per hour: 50 / (25/2) 50 * 2/25 100/25 = $4 per hour I'm not Ms. Sue but I hope you can trust my answer. Hope this helps :3

**math check**

Instead of multiplying 14.6 by 2, you should have divided it by 2.

**chemistry**

Recall that molarity is just moles of solute per liter of solution: M = n / V Since we're given the volume and molarity, we solve for the n: 0.30 M = n / 0.15 L n = 0.3 * 0.15 n = 0.045 mol CH3OH The problem asks for the mass of CH3OH. To get the mass, we multiply the numb...

**Math**

1. Yep 2. You would have to multiply 15% by 38, because it's asking for the number of students who did NOT pass their test. 38 * 0.15 = 5.7 or approximately equal to 6 students 3. Let n be the sales price It was said that 52% or 0.52 of the sales price is the profit. Thus,...

**honormath3**

-(35/4 * 3/7) / (-4/3) -(105/28) / (-4/3) -105/28 * (-3/4) 315/112 = 45/16 hope this helps :3

**college algebra**

ln y = log 9 e^(ln y) = e^(log 9) y = e^(0.9542) y = 2.5967

**college algebra**

ln y = -0.35 e^(ln y) = e^(-0.35) y = e^(-0.35) y = 0.7047

**math**

We must change first the 2 1/2 to improper fraction: 2 1/2 = 5/2 then we divide: 5/2 / (1/4) 5/2 * 4/1 20/2 = 10 people hope this helps :3

**Math**

We divide the area by the width to get the length: L = (x^2 - 5x - 10) / (x + 2) I don't think this can be simplified further. hope this helps :3

**Math Can someone check my answers ?**

Yes. ;)

**Math Can someone check my answers ?**

Yes it's B. Though the term surface area is for 3D shapes. But I guess it's fine, since it's still area anyway. ^^

**Math Can someone check my answers ?**

Are you sure it's "surface area" and it's "circle"? Because usually if the shape is 2D, the term is 'area' only. If it's "area of a circle" only, A,circle = pi*r^2 A,circle = 153.9 in^2 (closest to letter B) If it's "s...

**Math**

#1. I'm not sure if you mean x - sqrt(x-2) = 4 or x - sqrt(x) - 2 = 4, but I'll go with the first. x - sqrt(x-2) = 4 To do this, we isolate the term with squareroot to one side of equation: x - 4 = sqrt(x-2) Then we square both sides and solve for x: (x - 4)^2 = (sqrt(...

**Math**

Hi. I've seen your previous post. I'll try answering them. :) (9n+1)squared = 9 We expand the term with the square: (81n^2 + 18n + 1) = 9 81n^2 + 18n + 1 - 9 = 0 81n^2 + 18n - 8 = 0 Factoring, (9n + 4)(9n - 2) = 0 n = -4/9 and n = 2/9 Note that there are two values of ...

**Math**

(9n+1)squared = 9 We expand the term with the square: (81n^2 + 18n + 1) = 9 81n^2 + 18n + 1 - 9 = 0 81n^2 + 18n - 8 = 0 Factoring, (9n + 4)(9n - 2) = 0 n = -4/9 and n = 2/9 Note that there are two values of n. The sign that looks like a check mark in #2 is a squareroot sign. I...

**SAT math**

formula for slope: m = (y2 - y1)/(x2 - x1) where (x1,y1) and (x2,y2) are the points on the line. Substituting, -3/5 = (4 - 1)/(1 - x) -3(1-x) = 5(3) -3 + 3x = 15 3x = 18 x = 6 hope this helps :3

**Math**

p^2 - q^2 = 12 p + q = 4 We have two equations and two unknowns, so we can solve for the values of p and q. What we'll do is substitution. We choose one equation, and choose one variable and express it in terms of the other variable. In this case, we choose the second, and...

**Math**

That's correct. :) formula for slope: m = (y2 - y1)/(x2 - x1) where (x1,y1) and (x2,y2) are the points on the line. Substituting, -3/5 = (4 - 1)/(1 - x) -3(1-x) = 5(3) -3 + 3x = 15 3x = 18 x = 6 hope this helps :3

**math**

We just solve it like a real equation. Though remember that when a negative number is multiplied or divided to both sides of equation, the sign is reversed. 3(3F − 3) > 4F − 5 9F - 9 > 4F - 5 9F - 4F > 9 - 5 5F > 4 F > 4/5 Hope this helps :3

**6th grade math**

1. It's actually 2a - 18 2. Yep 3. Yep 4. Yep 5. Yep 6. Yep 7. Yep 8. Yep 9. Yep 10. I guess it's okay 11. Yep 12. Yep 13. 2^4 = 16 ; (the base 2 stands for the 2 people and 4 is the number of rounds) 14. Hmmm, "four multiplied by the sum of nine and twenty-three&...

**math**

x^2 - y^2 - 2y - 1 x^2 - (y^2 + 2y + 1) x^2 - (y+1)^2 (x - (y+1)) (x + (y+1)) (x - y - 1)(x + y + 1) Hope this helps :3

**algebra 2**

2(x-5) >= 6(x-3) 2x - 10 >= 6x - 18 2x - 6x >= 10 - 18 -4x >= -8 x <= 2 Hope this helps :3

**MATHS**

fifth of one and a quarter: (1/5)*(1 1/4) = (1/5)*(5/4) = 1/4 one and a quarter: 1 1/4 = 5/4 adding them, 1/4 + 5/4 = 6/4 = 3/2 = 1 1/2 Hope this helps :)

**chemistry**

I am not sure if you have a typo, but for the reaction to be balanced, that should be Nitrous Acid (HNO2) in the reactant side: 3HNO2 -> HNO3 + H2O + 2NO Note that all the species here are neutral (zero charge). Thus the sum of the individual charges of each element involve...

**Algebra**

I've never encountered this AC method before, but I've tried to google it. It's easy though it's crazy. XD Anyway, #1. I'll change the variable into x so it won't be confusing: 2x^2 + 3x + 1 First step is to multiply a (the numerical coeff of x^2) by c ...

**Math HELP URGENT!**

A. Factors of denominators: (x^2-z^2) = (x+z)(x-z) (x^2-2xz+z^2) = (x-z)(x-z) Thus, LCD : (x+z)(x-z)(x-z) B. Factors of denominators: (x^2-64) = (x-8)(x+8) (40-5x) = -5(x-8) x = x Thus LCD : -5x(x-8)(x+8) Hope this helps :3

**Math-correction**

*lol I'm sorry the smaller time is t = 4s. OMG XD

**Math**

To get the time, we just substitute h = 592 to the equation: h = 212t - 16t^2 592 = 212t - 16t^2 16t^2 - 212t + 592 = 0 4t^2 - 53t + 148 = 0 Factoring, (t - 4)(4t - 37) = 0 t = 4 s t = 37/4 s Since it requires the time in which the rocket FIRST reaches a height of 592, we choo...

**algebra**

We just solve it like a real equation. But then, if you multiply or divide a negative number on both sides, the sign will be reversed. 4 - 3w >= 8 -3w >= 8 - 4 (-3w)/(-3) >= 4/(-3) w <= -4/3 Hope this helps :3

**Geometry**

Use cosine (let x = angle): cos (x) = 3/12 Solve for x.

**Math**

1. Yep 2. The more complete set would be A. 3. Yep 4. It's actually D. Note that to say that a number is divisible by 9, the sum of the digits should be divisible by 9. Here, 5229 : 5+2+2+9 = 18, and 18 is divisible by 9. Hope this helps :3

**Math...help**

A & B are correct. In C, the (-) sign should be (+) because 12 minus 9 is positive 3. In D, combine the constants: 8 + 6d - 12 = 6d - 4 In E, combine the terms with variables: 30e + 18 - 8e = 22e + 18 In F, 15f + 10 - f - 5 = 14f + 5 hope this helps :3

**math**

Use the pythagorean theorem: c^2 = a^2 + b^2 where c = hypotenuse a = one leg b = the other leg In the problem, a = 9 b = 12 Now solve for c using the equation above.

**math**

If a point is reflected over the y-axis, the y-coordinate of the new point is equal to the original, while the x-coordinate is the negative of the original. Therefore, if the point is (8, -10), the reflected point is at (-8, -10). Hope this helps :3

**Math**

The conversion is 1 yard = 3 feet. Thus, 1 yd^3 = 3^3 ft^3 or 27 ft^3 If there are 3 yards, 3 yd^3 = 3 * 27 ft^3 = 81 ft^3 You're correct. :)

**math**

Recall that are of triangle is just A = (1/2)bh where b = base h = height It was said that the base is half of the height, or b = (1/2)h. Substituting to the formula, A = (1/2)(1/2)h*h 121 = (1/4)*h^2 484 = h^2 h = 22 m Solving for the base, b = (1/2)*22 = 11 m Hope this helps...

**Substituion MATH**

It's wrong, I don't know how you checked but x = 32 and y = 6 actually doesn't satisfy either given equation. Anyway, okay let's do #2. -1/2x - 1/4y = 3 1/3x + 1/6y = 2 To deal with fractions, it's easier if you first make them whole numbers by multiplying ...

**Substituion MATH**

#1. -x + 10y = 60 -4x + 16y = 32 If we need to use the substitution method, we choose an equation and let one of the variable in terms of the other. Then we substitute it to the other equation. Here, let's choose the first equation. -x + 10y = 60 Then let's choose the ...

**math (please help)**

#1. Note that horizontal line has a zero slope, and in the form y = c, where c is a any real number. Therefore, if it passes thru the point (-8,8), the equation must be y = 8. #2. If we are given the two points on the line, we first get the slope using the formula m = (y2 - y1...

**math**

Let A = cost of one apple Let P = cost of one ponkan According to the first statement, 4A + 2P = 53 According to the second statement, 2A + 4P = 75 Now we're looking for 6A + 6P (because half a dozen is equal to six). Notice that if we add the equations, we'll get 6A +...

**8th grade chemistry**

C. NaHCO3 It actually contains 6 atoms. :3

**Geometry**

#1. I believe there should be a given figure... #2 & #3. We need the choices...

**Calculus**

Get the derivative with respect to x: f(x) = -2x^3 + 33x^2 - 108x + 2 f'(x) = -6x^2 + 66x - 108 Let f'(x) = 0 and get the values of x: 0 = -6x^2 + 66x - 108 0 = x^2 - 11x + 18 0 = (x - 2)(x - 9) x = 2 and x = 9 Therefore, A = 2 and B = 9. At (-Inf , 2] : decreasing (be...

**chemistry**

The reaction is P4 + O2 -> P2O5 Balancing, P4 + 5 O2 -> 2 P2O5

**Physics**

*lol sorry, in the last calculation that should be 5.125 * 10^-11 * 6.022 * 10^23 but the answer is still the same. :)

**Physics**

Since the gas is ideal, we can use the Ideal Gas Law: PV = nRT where P = pressure in atm V = volume in L n = number of moles of air R = universal gas constant = 0.0821 L-atm/mol-K T = temperature in K We first convert the given in the appropriate units: V = 19.4 cm^3 cm^3 is a...

**Ap chemistry**

We first write the balanced chemical reaction: 4 Mn + 3 O2 -> 2 Mn2O3 ; ΔH = -962.3 kJ/mol Mn2O3 We then get the number of moles Mn by dividing the given mass by molar mass of Mn. The molar mass of Mn is 54.94 g/mol (get a periodic table and search for it). 6.4 / 54.94...

**algebra**

You forgot to type the function...

**Gen Chem 2**

f (# of equivalents) is equal to number of ionizable H+ (in acid-base titration), though it has also other meaning, for instance, in electrochemistry. Here, f = 2 because H2SO3 has 2 H+.

**GCC**

In the activity series, Na is more reactive than Mg, thus it can displace Mg: Mg(NO3)2 + Na -> NaNO3 + Mg Balancing the reaction, Mg(NO3)2 + 2Na -> 2NaNO3 + Mg Hope this helps :)

**Maths**

Your solution and answer are actually both correct. :)

**chemistry**

lol I think you forgot to put the arrow symbol somewhere in those reactions. But it can still be answered. The answer is Ba(NO3)2(aq) + Na2CrO4(aq) -> BaCrO4(s) + 2NaNO3(aq) This is just a double displacement reaction. And looking at the charge of each element involved (in ...

**Math**

No, you don't have to. 30 / 3 = 10 Here, 10 is positive because both 30 and 3 are positive. 30 / -3 = -10 While here, one of them is negative so the answer must also be negative. *Note that if however, both 30 and 3 are negative, the answer is positive.

**Math**

Your solution and answer are actually correct. :) Let's do the checking part: Y = 4Y + 30 if Y = -10, -10 = -10(4) + 30 -10 = -40 + 30 -10 = -10 Since both sides of the equation are equal, then Y is indeed equal to -10. Hope this helps :3

**Pre-Calculus**

So we must transform tan(A) + cot(A) into csc(A)*sec(A). tan(A) + cot(A) Note that cot(A) is equal to 1/tan(A). Substituting, = tan(A) + 1/tan(A) = (tan^2 (A) + 1) / tan(A) Recall the pythagorean identity: tan^2 (A) + 1 = sec^2 (A). Also tan(A) = sin(A)/cos(A) and sec(A) = 1/c...

**Geometry**

I believe there should be a given figure in the problem...?

**Math**

If you mean, 5^(2-x) = 7^(5x + 7) Then, we take the ln of both sides (2-x)*ln(5) = (5x + 7)*ln(7) 1.609*(2-x) = 1.946*(5x+7) Solving for x, x = -0.9174 Hope this helps :3

**Alg 2**

y varies directly with x: y = kx where k is some constant. To find this k, substitute the given x and y: 64 = k(16) k = 64/16 k = 4 To find x, substitute y = 288 and k = 4: 288 = 4x Now solve for x. Hope this helps :3

**college algebra**

Go to wolframalpha. com and type the given.

**Maths**

If you draw this one, you would actually form a right triangle, where the hypotenuse is the length of the ladder (15 ft), and one of the legs is the distance from the wall to the bottom end of ladder (9 ft). What we're looking for is also the length of the other leg. Recal...

**math**

Yes, it's correct.

**cal**

Recall the chain rule. If two expressions which are functions of x are multiplied, we do the following: h(x) = f(x)*g(x) h'(x) = f'(x)*g(x) + f(x)*g'(x) As we can see, the derivative of h(x) is the derivative of f(x) multiplied by the original g(x), plus the deriva...

**cal**

If you mean f(x) = x^8√(5-3x), then f'(x) = (8x^7)*√(5-3x) + (-3/2)*(x^8) / √(5-3x)

**Algebra**

Yes, they are all equivalent. To prove, assume a real value of x, for instance, x = 2. Then we substitute this value to each expression. The answers must be equal since the expressions are equivalent: 1800(x+20) ; x=2 1800(2+20) = 1800(22) = 39,600 1800x + 20(1800) ; x=2 1800(...

**math**

(a) To get the maximum profit, we differentiate the given function with respect to u. And then equate everything to zero (because at maximum, the slope is zero): P = -0.032u^2 + 46u - 3000 dP/du = -0.064u + 46 0 = -0.064u + 46 0.064u = 46 u = 718.75 (this is the number of unit...

**math-correction**

*lol, sorry it shouldn't be dA/dt, rather dA/dW = 62.5 - 2W but it won't affect the answer anyway. (it's just that you might wonder where the variable t came from) ^^;

**math**

Since there is additional 15 m which is part of one side of the wall, we can say that the total fencing material is 110 + 15 = 125 m Recall that perimeter of rectangle is just P = 2(L + W) where L is the length and W is width. Substituting, 125 = 2(L + W) 62.5 = L + W, or L = ...

**math**

Let A = number of Aaron's cards Let B = number of Benga's cards From the first statement, the total number of their cards is 976, so A + B = 976 From the second statement, B = 7A Thus we can say, A + 7A = 976 8A = 976 A = 122 B = 854 Now, let x = number of cards that B...

**chemistry**

First separate the reaction into reduction and oxidation reactions. Then add the right number of electrons to balance the charges. Reduction: Mn(2+) -> Mn(5+) Mn(2+) -> Mn(5+) + 3e- Oxidation: Sn(2+) -> Sn Sn(2+) + 2e- -> Sn And then balance both reactions such tha...

**Algebra**

Let n be the number (n / -9) + 10 = 11 Solving, -n / 9 = 11 - 10 -n / 9 = 1 n = -9 Hope this helps :3

**Math**

Is that division, like this, (2^4 * 3^9) / (3^5 * 2^7) ? If it is, then, yep, the answer is 2^-3 * 3^4.

**Chemistry-correction**

*sorry, my conversion of 2.5 kg to g is wrong. The equation should be Q = (2500 / 200.6)*(28.0)*(-6 -(-20))

**Chemistry**

Through out the temperature range, Hg remains as liquid. Recall that heat released or absorbed is given by Q = m*c*(T2 - T1) where m = mass c = specific heat T = temperature Note that molar mass of Hg is 200.6 g/mol. Substituting, Q = (250000 / 200.6)*(28.0)*(-6 -(-20)) Q = ? ...

**math**

Slope intercept form is y = mx + b. We just convert the given equation in this form: 2x + y = -7 y = -2x - 7

**college algebra**

sqrt(x) + 7 Domain is the set of all possible values of x. Here, note that x is inside a squareroot radical sign and therefore cannot be less than zero. Thus domain is all real numbers greater than or equal to zero. In symbols: [0 , +infinity) Hope this helps :)

**math**

x^2 + x - 20 = (x + 5)(x - 4)

**math**

x^2 + 9x +18 = (x + 3)(x + 6)

**Algebra 1**

Yes, the ninth term is 2. :) Just substitute n = 9 to the formula: A = -14 + (9-1)(2) A = -14 + 8(2) A = -14 + 16 A = 2

**college physics**

a. Of course, one way for athlete 1 to overtake athlete 2 is for him to accelerate (that is, if v2 > v1). But since the given are constant speeds, surely v2 MUST BE LESS THAN v1 in order for athlete 1 to overtake athlete 2, WITHOUT accelerating. b. Recall that the distance ...

**Science help! URGENT. Check answers**

1. Nope. If the net forces are zero, it means that the object is at an equilibrium state (may be static of dynamic), and thus implies the forces cancel or balance each other out. 2. It's actually air resistance. I suggest you read about Aristotle's and Galileo's ex...

**chemistry**

It's an exothermic reaction, since heat is released.

**MATHS**

By trial and error: Perry's age = 73 Laura's age = 37 Difference of their ages = 36 years Checking: 73-1 = 2(37-1) 72 = 2(36) 72 = 72

**Pre-Calc**

f(x) = (x^5+3x^3+5x) / (4x^4+2x^2) The only common factor of numerator and denominator is x, but it isn't really necessary to cancel it. i. Vertical Asymptote To get this, we get the limit of x, as f(x) approaches infinity. lim x as f(x)->infinity Or easier way is to ge...

**Math**

1. Yep 2. Yep 3. Yep

**math**

a. As the problem hinted, Let x = number of weeks Let y = dollars saved For the first equation: you have initially $50, and $10 is added each week. Therefore, at the end of x weeks, the total amount of money you'll have is, y = 50 + 10x For the second equation: same analys...

**Math**

Yes, x can be -13 or 13.

**maths**

What is the operation? Are we to divide them? And, please clarify the 13^1/2x^2, if it's 13^(1/2 x^2) or 13^(1/(2x^2)).

**math**

Let x = Mary's age The condition given, in symbols, is x + 10 = 2x - 5 Solving for x, x - 2x = -10 - 5 -x = -15 x = 15 years old hope this helps ;)

**chem 211**

Write the balanced chemical reaction: C2H4 + H2 -> C2H6 , ΔH = -144 kJ/mol C2H4 Then we get the number of moles of C2H4 using the given mass, 14.6 kg of C2H6. Molar mass, C2H6 = 2*12 + 6*1 = 30 g/mol n,C2H6 = 14.6 * 1000 g / 30 g/mol = 486.67 mol Since the mole ratio f...

**chem**

Recall that the heat absorbed (+) or released (-) by a substance is given by Q = mc(T2 - T1) where m = mass (g) c = specific heat capacity (J/g-K) T2 = final temperature T1 = initial temperature Note that in the problem, the source of energy or heat came from the alloy. Thus w...

**math**

Let x = capacity of carton Let y = capacity of cup According to the first statement of the problem, x = 2y According to the second statement, 1.8 = 3y + 2x Now, we have the equations. What we'll do is substitute the first equation to the second: 1.8 = 3y + 2(2y) 1.8 = 3y +...

Pages: <<Prev | 1 | **2** | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | Next>>