Tuesday

June 28, 2016
Total # Posts: 41,478

**algebra**

recall that (a-b)(a+b) = a^2-b^2 (x+3)/(√2-3x) * (√2+3x)/(√2+3x) = (x+3)(√2+3x)/(2-9x^2) or something, depending on whether you were sloppy with your parentheses.
*May 24, 2016*

**Calculus**

how advanced is "advanced"? trig substitution? polynomial roots? try and meet us halfway here. Surely your text has examples where u has been substituted for some expression. Do something similar. Then tweak some constant so the answer comes out 6.
*May 24, 2016*

**math**

sec(θ)/(csc(θ)-cot(θ)) - sec(θ)/(csc(θ)+cot(θ)) becomes sec(θ)(csc(θ)+cot(θ)) - sec(θ)(csc(θ)-cot(θ)) ---------------------------------------------------------- (csc(θ)-cot(θ))(csc(θ)+cot(θ)) Now ...
*May 24, 2016*

**MATHS**

24.5*13*4 * 7.48 * 0.80
*May 24, 2016*

**trigonometry**

sec(θ)/(csc(θ)-cot(θ)) - sec(θ)/(csc(θ)+cot(θ)) becomes sec(θ)(csc(θ)+cot(θ)) - sec(θ)(csc(θ)-cot(θ)) ---------------------------------------------------------- (csc(θ)-cot(θ))(csc(θ)+cot(θ)) Now ...
*May 24, 2016*

**MATHS**

You appear to be adding, not subtracting. Also, 3/4 - 1/2 = 1/4 so the answer cannot be a whole number.
*May 24, 2016*

**geometry(is this right?)**

(-3,1)x4 = -12,4 (-1,4)x4 = -4,16 (2,3)x4 = 8,12 (4,-3)x4 = 16,-12 Not sure how you cam up with those other bizarre answers
*May 24, 2016*

**Math**

I suspect a typo. The difference cannot be more than 9, so the number must be at most 18. It is even, so the only candidates are 10 12 14 16 18 None of those works.
*May 24, 2016*

**math**

that's better
*May 24, 2016*

**math**

#1 nope. Odd, since you got it right in your previous post. #2 same comment #3 ok #4 nope - subtract powers when dividing #5 same comment #6 nope. Odd, since you got #3 right #7 ok #8 nope. look carefully. write out the products if you must. see what cancels in the division. ...
*May 24, 2016*

**math**

both ok. good work.
*May 24, 2016*

**MATHS**

Looks like #3,6 to me since |a| > |b| and b<0, c is positive and between b and a.
*May 24, 2016*

**Mathematic**

in principle, it would be either 2950(1+.0810*1.5) or 2950(1+.0810)^(1.5) but, if it accrued annually, you will not yet have received the interest for the 6 months of the 2nd year. As you see, it can get complicated.
*May 24, 2016*

**math**

t = 7s s is independent. The total cost depends on the number of students attending.
*May 24, 2016*

**@Reiny**

oh, sure - read the topic carefully. show-off.
*May 24, 2016*

**linear-equations-in-one-variable**

If the width is x and the length y, then y = x+4 (x+3)(y+3) = xy+81 Now just solve for x and y. If you expand the 2nd equation, you will see the xy drop out, leaving you with two linear equations in x and y.
*May 24, 2016*

**Algebra**

If the plane's speed is p and the wind speed is w, then we have 14(p-w) = 3024 9(p+w) = 3024
*May 24, 2016*

**Algebra**

c+a = 2200 1.50c + 4.00a = 4550.00
*May 24, 2016*

**Algebra**

I assume you want to know how many miles in city and highway. Well, take a look at the data: miles = gals * mi/gal so total miles: 15.867*15 = 238 If there were c city miles, then the rest (238-x) were highway miles. So, x/13 + (238-x)/30 = 15.867 x = 182 so, 182 city miles 56...
*May 24, 2016*

**Algebra**

since distance = speed * time, 3(x+3) = 7(x-3)
*May 24, 2016*

**math**

(80000-50000)/50000 = 3/5 = 60%
*May 24, 2016*

**algebra**

however, assuming you meant y = -1/3 x + 1/2, if you rearrange things you have 6x + 18y = 9 1/3 x + y = 1/2 or 6x+18y = 9 2x+6y = 3 you can see that they are the same line.
*May 23, 2016*

**Math**

don't you have the formula? Just plug in your numbers and we can check your answer.
*May 23, 2016*

**Math**

correct.
*May 23, 2016*

**Math**

rearrange things to a single format: x+6y=4 2x+12y=8 Now you can see that they are really the same line.
*May 23, 2016*

**Math**

well, you must have tan2x = 0 or sinx = 1 so, you are almost right. tan2x=0 if 2x = 0 or π or 2π or 3π so, x = 0, π/2, π, 3π/2 sinx = 1 if x = π/2, so that does not add any solutions to the list.
*May 23, 2016*

**Math**

If all the numbers are expressed as multiples of 10^-7, they are a: 620 b: 12.3 c: 52000000000 d: 370 should be a bit easier now, eh?
*May 23, 2016*

**College Algebra math**

35 + √(37^2 - 35^2)
*May 23, 2016*

**pre algebra Is it A,B,C or D?**

where did you come up with 3/11? tossing the coin and picking a letter are independent events, so the theoretical probability is just 1/2 * 1/5 = 1/10
*May 23, 2016*

**Geometry**

well, s = rθ
*May 23, 2016*

**Pre algebra Am I right??**

looks good to me
*May 23, 2016*

**math**

A farmer has dogs and chickens running around in his backyard. There are a total of 36 animals, and the farmer counts a total of 56 legs. The farmer can use a system of equations to determine how many of each animal there are. He claims that one of the equations in the system ...
*May 23, 2016*

**Math**

C: 3 is prime and odd
*May 23, 2016*

**ALGEBRA**

nope. You have to account for both events. P(odd) = 3/4 P(even) = 1/4 so, P(odd,even) = 3/4 * 1/4
*May 23, 2016*

**Algebra**

11 bills in all The two bills must be 5,20 or 20,5 p = (2/11 * 4/10) + (4/11 * 2/10) = 8/55
*May 23, 2016*

**Algebra**

correct
*May 23, 2016*

**Math**

for the product to be even, you must have either m even or m+p even A works, because odd+odd is even B fails -- odd*odd = odd C works whether p is even or odd, so it's not true that p must be even. D the same
*May 23, 2016*

**Math**

so did I
*May 23, 2016*

**Math**

yes it would
*May 23, 2016*

**Math**

right on.
*May 23, 2016*

**Math (Vectors)**

if the angle A is drawn in the standard position, tan(A) = y/x
*May 23, 2016*

**MATHS TRIGONOMETRY**

you have sinθ = 2/3 if sin and cos are both positive, then θ is in QI. So, now draw the triangle. y = 2 r = 3, so x = √5 Now just use those values and the fact that sinθ = y/r cosθ = x/r tanθ = y/x to answer the questions. The last one should be ...
*May 23, 2016*

**math**

rearranging things a bit, you have 3y^2 - y - 6 = 0 y = (1±√(1+72))/6
*May 23, 2016*

**math hurry**

1 nope. subtract exponents when dividing 2 nope. same reason 3 nope. 4^-2 = 1/4^2 = 1/16 4 nope. using the logic of the first 3 problems, 5^0 = 5^1/5^1 = 5/5 = 1 any number to the zero power is 1. #6 I suspect a typo, as they are all wrong #7 B (But I suspect that you did it ...
*May 23, 2016*

**Math Can you help me?**

gains are positive, losses are negative, so he ends up at 0+7-4+12 = 15
*May 23, 2016*

**math**

certain superstores will often price match or even beat a competitor's price by 10%.the function g(x)=0.90x represents the sale price of a piece of merchandise at such a superstore.the function f(x)=0.13x represents the HST owed on a purchase with a selling price of x ...
*May 23, 2016*

**Math**

think of it kind of like a Venn diagram. P(divisible by 2 or 5) = P(by 2)+P(by 5) - P(by 10) So just count the number of integers divisible by 2 or 5, and you have counted the multiples of 10 twice. Divide that answer by 1000 to get the probability.
*May 23, 2016*

**Math; Solve by Graphing**

clearly D is out, since it has nothing to do with the solution. Similarly, B and C are out, because it does not matter where the lines hit the axes. The solution is where both equations are true. Since each represents a line, that is where the lines intersect. So, (A) is the ...
*May 23, 2016*

**Math**

first, review what complementary and supplementary mean. An angle and its complement sum to 90 degrees. So, what number do you add to 52 to get 90? similarly for supplement.
*May 23, 2016*

**analytic geometry**

The two lines you named are parallel. They cannot be the asymptotes of an hyperbola.
*May 23, 2016*

**math**

c = kq
*May 23, 2016*

**Geometry,Math**

you are correct that a cylinder has less surface area than a rectangular prism.
*May 22, 2016*

**Math**

A farmer has dogs and chickens running around in his backyard. There are a total of 36 animals, and the farmer counts a total of 56 legs. The farmer can use a system of equations to determine how many of each animal there are. He claims that one of the equations in the system ...
*May 22, 2016*

**Math**

total marbles = 22 so, P(blue,yellow) = 9/22 * 13/21
*May 22, 2016*

**science**

well, rice grains are bigger than sugar grains. So just use a fine sieve. Sugar goes through, rice stays behind.
*May 22, 2016*

**Math**

A farmer has dogs and chickens running around in his backyard. There are a total of 36 animals, and the farmer counts a total of 56 legs. The farmer can use a system of equations to determine how many of each animal there are. He claims that one of the equations in the system ...
*May 22, 2016*

**grade 9**

28*22*h = π*3.5^2*40 h ≈ 2.5m
*May 22, 2016*

**Math**

A farmer has dogs and chickens running around in his backyard. There are a total of 36 animals, and the farmer counts a total of 56 legs. The farmer can use a system of equations to determine how many of each animal there are. He claims that one of the equations in the system ...
*May 22, 2016*

**Easy Math**

I think you are correct. If the points in order are A,B,C then each point can be the start of a ray, and each ray can go in two directions. But rays from A and C must also include B. So, the rays are AB (or AC, which is the same) BA and BC CB (or CA)
*May 22, 2016*

**pre-algebra**

there are infinitely many possible values: 2(30+L) >= 768 30+L >= 384 L >= 354 so, any number at least 354 will work. I suspect you did not ask the right question.
*May 22, 2016*

**Algebra**

2(w + 3w-4) = 48 find w, and then you can get the length.
*May 22, 2016*

**integral calculus**

Draw a cross-section. If the oil is at depth y, then the width of the thin rectangle of oil is 2x, where (3-y)^2 + x^2 = 9 x = √(6y-y^2) So, the weight of oil for that thin sheet is 2x*8*60 dy and the total work to lift all the oil out of the top of the tank is thus &#...
*May 22, 2016*

**maths**

Fix the typo (ax^2+bx+x ?), and is the curve tangent to the line?
*May 22, 2016*

**math**

assuming the strides take the same amount of time, the dog wins. 1.30 * 0.70 = 0.91
*May 22, 2016*

**Mathematics**

well, S10 = 10/2 (1+19)
*May 22, 2016*

**math (check answer)**

why would the math class have students whose birthdays are skewed?
*May 21, 2016*

**math**

since the events are independent, just multiply their probabilities. For the first, that would be 1/6 * 1/2 and the others likewise
*May 21, 2016*

**Math**

just crank out the algebra. The result is 4 note that w = cis(2pi/3) or cis(4pi/3)
*May 21, 2016*

**expansion help**

scroll down and down at http://www.wolframalpha.com/input/?i=%281%2B%281%2Fx^3%29%29
*May 21, 2016*

**Math**

f+s = 72 f+2 = 3(s+2)-4 now just crank it out.
*May 21, 2016*

**Math**

4 hours = 240 minutes. So, the fraction of the tank filled in one minute is 1/15 - 1/240 = 15/240 = 1/16 So, it will take 16 minutes to fill the leaking tank
*May 21, 2016*

**geometry**

an unusual position -- the ladder is not on the ground. I expect you mean the foot of the ladder is one meter from the wall. I assume you want the height of the top of the ladder. If the height up the wall is h, then 1^2 + h^2 = 20^2
*May 21, 2016*

**Middlesex**

recall that if a is a root, then (x-a) is a factor of f(x). So, you have (x-3)(x+6) = 0
*May 21, 2016*

**ordinary differential equation**

well, it's clear that (m-3)^3 = m^3 - 9m^2 + 27m - 27 now just proceed as usual to solve this type of equation.
*May 21, 2016*

**math**

depends on the distance, no? But, you know that after n seconds, the distance traveled will be Sn = n/2 (2*1.5+0.4(n-1)) cm
*May 21, 2016*

**math**

z = 1250ln(yx^2)+45(y^2+x)(x^3 -2y)-(xy)^1/2 see ∂z/∂x at http://www.wolframalpha.com/input/?i=1250ln%28yx^2%29%2B45%28y^2%2Bx%29%28x^3+-2y%29-%28xy%29^1%2F2 But you will need some values for x and y if you want a numeric value.
*May 21, 2016*

**Maths**

surely you can plot each of these curves. But just to remind you, http://www.wolframalpha.com/input/?i=plot+y%3Dsinx,+y%3Dcosx,+y%3Dcosx-sinx
*May 21, 2016*

**logarithm math-need help!!!!**

If we let u = log_4(x) then x = 4^u and we have 5u + 48/u = 4^u/8 the solution to this is u=4 so, x=4^u = 256
*May 21, 2016*

**math**

a factor of 1000 means that one 6 is 3 places to the left of the other. That is, the number must contain the digit string 6336 That means that the other 3 must go on the left or right end.
*May 21, 2016*

**Mathematics**

w(w+3) = (w/2)(w+3 + 5) w = 2 be sure to check that this works.
*May 21, 2016*

**geometry**

dv/dt = 4πr^2 dr/dt da/dt = 8πr dr/dt (dv/dt)/(da/dt) = r/2 so, when r=10, da/dt = 240 cm^2/s
*May 21, 2016*

**Math**

a mess, is what. Still, I will try to parse your garbled sentence. 9 - 3 ÷ 1/3 + 1 = 1 If that's not what you meant, try using some parentheses to get what you want.
*May 21, 2016*

**maths**

original: (d-3)/d now, adding 1's, we have (d-3+1)/(d+1) = 5 Hmmm. I suspect a typo, since d is not an integer.
*May 21, 2016*

**math**

$(40*0.90-10)*1.45 = $37.70
*May 20, 2016*

**math**

clearly the numbers in question must have 6336 so, there are two 3's left over, which must go on the ends: 36336 63363
*May 20, 2016*

**Algebra**

you show B and D the same. Pick the one which is really 6^x x^6 is not what you want. That is (0,0),(1,1),(2,64)...
*May 20, 2016*

**math**

oh come on. either 4cotx+3 = 0 cotx = -3/4 or cotx-1 = 0 cotx = 1 In the first case, x will be in QII or QIV on the second case, x will be in QI or QIII
*May 20, 2016*

**math**

since csc^2 = 1+cot^2, 4(1+cot^2x)-7 = cotx 4+4cot^2x-7 = cotx 4cot^2x - cotx - 3 = 0 (4cotx+3)(cotx-1) = 0 Now it's easy, right?
*May 20, 2016*

**Algebra**

1*57 + 6*x = 5(57+x)
*May 20, 2016*

**pre-algebra**

x + 1/3 x = 84 4/3 x = 84 ...
*May 20, 2016*

**HELP ME ! DESPRATE MATH STUDENT !!**

you cannot compare those integers with 6 1/3 ? You are in deep doodoo. At the very least, grab a calculator and subtract each from 6.333333 If the result is positive they are less; if negative, they are greater.
*May 20, 2016*

**HELP ME ! DESPRATE MATH STUDENT !!**

well, geez, did you try a few values? 3*0 - 4 <= 15 ? 3*6 - 4 <= 15 ? and so on. or, algebraically, 3x-4 <= 15 3x <= 19 x <= 19/3 so, how many of those values fit the bill?
*May 20, 2016*

**math**

original value: n/d new value: 1.60n/0.80d = 2n/d so, it has grown by 100%
*May 20, 2016*

**math**

5/300 x = 475/100
*May 20, 2016*

**math**

6/5 as many people, so 5/6 as much time
*May 20, 2016*

**math**

195/15 * 8
*May 20, 2016*

**math**

v/i = 5/2, so v = 5i/2 v = i+42 5i/2 = i+42 so, i=28 and v=70 You want to find x such that (70-x)/(28+x) = 3/4 I expect you can handle that part.
*May 20, 2016*

**math**

420/5 = 84 so, multiply all the values by 84 and you have 504:420:252 Now just add all that up.
*May 20, 2016*

**math**

15 + x = -84 ...
*May 20, 2016*

**MATH HELP PLEASE !!**

clearly, it also increases by 5 (x+5)-3 = (x-3)+5
*May 20, 2016*