Tuesday
June 28, 2016

Posts by STEVE

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

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