Sunday

September 21, 2014

September 21, 2014

Total # Posts: 27,130

**Algebra 1--Please, help me!**

1. for the x-intercept let y = 0 ---> x = 2/3 for the y-intercept , let x = 0 ---> y = -2 2. (3m^2 n)/(5m)(20mn/n^6) = (3mn/5)(20m/n^5) = 12m^2/n^4 ------> a) 3. 3/x + 3/(5x) LCD = 5x = 15/(5x( + 3/(5x) = 18/(5x)-----> c)
*June 9, 2014*

**Algebra**

domain: { -7,9,0} range : { 5,-4,3,-7}
*June 9, 2014*

**Algebra 1--Please, check my answer!**

1. the slope of x+2y = -6 is -1/2 so we are looking for a line with slope +2 so anything starting with 2x-y = .... or -2x + y = ... will do. looks like b) to me 2. They all factor and simplify a) 3(x+2)/((x+2)(x-1)) = 3/(x-1) , x ≠ -2 b) 3(x-1)/((x-1)(x-1)) = 3/(x-1) , x...
*June 9, 2014*

**algebra/can you show me how to solve problem**

f(x) = x^2 + 2 f(-3) = (-3)^2 + 2 = 9+2 = 11 notice that I substituted x with the given value of x wherever I saw an x do the others the same way
*June 9, 2014*

**Algebra 1--Please, help me!**

see later post
*June 9, 2014*

**Algebracan you answer my question**

http://www.wolframalpha.com/input/?i=plot+x-y%3D4+%2C+2x%2B3y%3D13+
*June 9, 2014*

**Math**

let y = -x^2 + 5x + 5 dy/dx = -2x + 5 = 0 for a max of y 2x = 5 x = 5/2 when x = 5/2 y = -25/4 + 5(5/2) + 5 = 45/4 you should recognize y = -x^2 + 5x + 5 as a downward opening parabola , the max is 45/4 when x = 5/2
*June 9, 2014*

**Calculus**

if f ' (x) = 2x- 3x^2 f(x) = x^2 - x^3 + c f(0) = 0-0+c f(3) = 9 + 27 + c = 36+c change from f(0) to f(3) = 36+c - c = 36
*June 9, 2014*

**algebra**

Your expansion is incorrect 3(x-5)(x+5) = 3(x^2 - 25) = 3x^2 - 75 Since you wanted a quadratic equation, it should be 3x^2 - 75 = 0
*June 9, 2014*

**algebra**

What did you get ?
*June 9, 2014*

**Algebra**

follow the same steps that I showed you in your previous post of the identical type of question. It appears you never even looked at it.
*June 9, 2014*

**Algebra**

that would simply be f(x) = 2(x+3)(x+4) = 2x^2 + 14x + 24
*June 9, 2014*

**Math**

1by1 --- 64 of them 2by2 --- 49 3by3 --- 36 4by4 --- 25 5by5 --- 16 6by ----- 9 7by7 ---- 4 8by8 ---- 1 total = 204 There can only be an equal number of reds and blacks in the even-numbered squares, so 64 + 36 + 16 + 4 + 1 = 121 121 blocks have the same number of reds and ...
*June 9, 2014*

**Probability!**

since you are replacing the marble, the second draw is not affected by anything you did before. so Prob(red, then blue) = (8/43)(12/43) = 96/1849
*June 9, 2014*

**MATH**

correct
*June 9, 2014*

**MATH**

For the first, the following are divisible by 3: 3 6 9 so what do you think?
*June 9, 2014*

**math.**

0 < (x+3)/2 < 5 multiply by 2 0 < x + 3 < 10 subtract 3 -3 < x < 7
*June 9, 2014*

**Algebra**

I think the main purpose of the question, even though they did not say that, was to show that the midpoint of the hypotenuse is equidistant from the 3 vertices. All I did with the slope calculation was to show that the triangle is indeed right-angled. Other than that, finding ...
*June 9, 2014*

**Algebra**

I don't understand your question. I DID use the distance between two points formula, I just did not show the subtraction since that is easily done in your head. here is one of them with all steps : AM = √( 2.5 - 1)^2 + (3.5-1)^2 ) = √( 1.5^2 + 2.5^2) = √2...
*June 9, 2014*

**Algebra**

Your diagram should show that you have a right angle at B , but let's prove it anyway. slope AB = (2-1)/(5-1) = 1/4 slope of BC = (6-2)/(4-5) = -4 YES, AB is perpendicular to BC, thus AC is a hypotenuse midpoint of AC = M( (1+4)/2 , (1+6)/2) = M(5/2 , 7/2) = M(2.5 , 3/5) ...
*June 9, 2014*

**Algebra**

(f*g)(x) = (2x+5)(x^2 - 3) = 2x^3 + 5x^2 - 6x - 15 do the other one in the same way
*June 9, 2014*

**trig**

let's fit the data to a curve of the type f(t) = a cos k(t +d) + c from highest to lowest = 65-25= 40 cm so a = 20 from highest to lowest = .3 s to 1.8 s so period = 3 seconds 2π/k = 3 k = 2π/3 so far we have f(t) = 20 cos (2π/3) (t +d) + c let's raise ...
*June 9, 2014*

**Maths, Divine International Public School**

cotA = 8/15 tanA = 15/8 so y=15, x=8 r^2 = 15^2 + 8^2 r = √289 = 17 sinA = 15/17 cosA = 8/17 then (1+SinA)(1-SinA)/(1+CosA)(1-CosA) = (1 - sin^2 A)/(1 - cos^2 A) = (1 - 225/289)/(1 - 64/289) = (64/289) / (225/289) = 64/225
*June 8, 2014*

**Math**

upwards: f(x) = (x+2)(2x+5) downwards f(x) = -(x+2)(2x+5) expand if needed
*June 8, 2014*

**Math 11**

I hope you made a diagram. label the window position P label the top of the statue T label the bottom of the statue B So we want TB I can find BP sin34° = 20/BP BP = 20/sin34 let's use the sine law in triangle TBP TB/sin4 = BP/sin120 TB = BPsin4/sin120 = (20/sin34)(...
*June 8, 2014*

**Math helpppp!**

You gave the equation in vertex form so the vertex is easily read to be (6,3) for standard form, just expand your function h(x) = x^2 -12x + 36 + 3 = x^2 - 12x + 39
*June 8, 2014*

**math**

Euler said: V + F - E = 2 so if 4 + 6 - E = 2 -E = -8 E = 8 It has 8 edges
*June 8, 2014*

**math**

This is the same as finding a Lowest Common Denominator 20 = 2*2*5 24 = 2*2*2*3 30 = 2*3*5 so we need: 2*2*2*3*5 or 120
*June 8, 2014*

**math**

let a^(2/3) = y for easier typing then x = y - 1/y = (y^2 - 1)/y x^3 = (y^6 -3y^4 + 3y^2 - 1) / y^3 = (a^4 - 3a^(8/3) + 3a^(4/3) - 1)/a^2 or a^2 - 3a^(2/3) + 3a^(-2/3) - a^-2 3x = 3a^(2/3) - 3a^(-2/3)
*June 8, 2014*

**math**

present age: michael ---- x max ------- x-5 4 years ago: michael ---- x-4 max ------- x - 9 x-4 + x-9 = 25 2x = 38 x = 19 Michael is now 19 , and Max is now 14 check: 4 years ago , Michael was 15 and Max was 10 was the sum of their ages at that time 25? YES
*June 8, 2014*

**Math**

The equation for your cost: cost = .1(m-500) + 25 , where m is in minutes so : .1(m-500) + 25 > 30 For the second part, m = 525 cost = .1(525-500) + 25 = $27.50
*June 8, 2014*

**Pre-Calc**

For any (r,Ø) x = rcosØ, y = rsinØ so x = 5cos(π/4) , y = 5sin(π/4) x = 5√2/2 , y = 5√2/2 so you have the point (5√2/2 , 5√2/2) (I don't see why you would want to write that in decimals, since you have to round it) ...
*June 7, 2014*

**Algebra confused/Thank you**

You should be able to read the solution. http://www.wolframalpha.com/input/?i=plot+3x+%2B+2y+%3D+5+%2C+4x+−+3y+%3D+1
*June 7, 2014*

**maths**

a+bi = √(1+i)/√(1-i) = √(1+i)/√(1-i) * √(1-i)/√(1-i) = √(1 - i^2) / (1-i) = √(1 - i^2) / (1-i) * (1+i)/(1+i) = √2(1+i)/2 = √2/2 + √2/2 i so a = √2/2 and b=√2/2 and a^2 + b^2 = 2/4 + 2/4 = 1
*June 6, 2014*

**Algebra**

Put Hobbinton at the origin (0,0) on the x-y grid then Tom's house would be (12,-16) distance from (0,0) to (12,-16) = √(12^2 + (-16)^2) = √400 = 20
*June 6, 2014*

**math**

prob(c) = 1/4 prob(not c) = 3/4 so you are looking for c c notc = (1/4)(1/4)(3/4) = 3/64 c notc c = (1/4)(3/4)(1/4) = 3/64 notc c c = (3/4)(1/4)(1/4) = 3/64 prob of your event = 3(3/64) = 9/64
*June 6, 2014*

**Algebra**

the way you typed it, there is very little simplification I multiplied top and bottom by x^2 to get (x^3 + 3 - 36x + 3x^2)/(x^3 + 3x^2) , and that's about it. If you meant: ( (x+3/x^2 -36/(x+3)) /( (x+3)/x ) it would be something totally different. I can't guess what ...
*June 5, 2014*

**MATH**

Pick any x say, x = 0 y = 2(0)-5 = -5 ----> the point (0,-5) how about x = 4 , (or any x you feel like) then y = 2(4) - 5 = 3 --- the point (4,3) plot (0,-5) and (4,3) , join the with a straight line, extend the line to any length you feel like
*June 5, 2014*

**math**

that would be 8 - choose - 4 = C(8,4) = 8!/(4!4!) = 70
*June 5, 2014*

**trig**

For your first one, You should recognize those numbers as belonging to the 30-60-90° right-angled triangle which would make c = 1 If you didn't notice that, you could use the cosine law c^2 = 2^2 + √3^2 - 2(2)(√)cos30° = 4 + 3 - 4(√3)(√3/2...
*June 5, 2014*

**math word problems**

original: x by x area = x^2 new dimensions: (x+3) and (x+2) new area = (x+3)(x+2) = x^2 + 5x + 6 x^2 + 5x + 6 - x^2 = 46 5x = 40 x = 8 original was 8 by 8 check: old area = 64 new is 11 by 10 new area = 110 change in area = 110-64 = 46 , yeahh!
*June 4, 2014*

**Precalculus**

#3 Those are permutations since the order matters a) start with a vowel: 2*5*4 = 40 , you were right b) all consonants, means we only pick from 4 4*3*2 = 24 , you were right c) all vowels, you are right with 0 since we only have 2 vowels and we need 3 d) all consonants , ...
*June 4, 2014*

**Math - Business Calc.**

I noticed an error in Damon's solution 4th line : V = (17-2h)(5-2h)h = (17-h)(5h-2h^2) should be : V = (17-2h)(5-2h)h = (17-2h)(5h-2h^2) I had h = 1.1445
*June 4, 2014*

**Algebra - Help!!**

I did a synthetic division of x^3 - 7x + 6 by x+3 to get the other dimension of x^2 - 3x + 2 , looks like a)
*June 4, 2014*

**Math**

Where is the second equation ?
*June 3, 2014*

**algebra math**

so she need one of 10, 11, or 12 prob of that = 3/12 = 1/4
*June 3, 2014*

**Algebra**

LCD is 24x -9y/(12x) + 28y/(12x) - 2y/(12x) = 17y/(12x)
*June 3, 2014*

**Math**

x^3 - x^2 - x + 8 = 0 tough one - it does not factor tried x = ±1, ±2, ±4 , none worked so no rational root what about real roots? let f(x) = x^3 - x^2 - x + 8 for f(-1) = -1 -1 +1 +8 = 7 for f(-2) = -8 - 4 + 2 + 8 = -2 so there is a real root between -2 ...
*June 3, 2014*

**math**

Did you make a sketch? I have a right-angled triangle with a base of 15 and a height of 4, (10 ft - his 6 ft) so in relation to your angle of elevation Ø, we have the opposite and the adjacent, suggesting tanØ = 4/15 arctan = 14.93° So to the nearest degree: ...
*June 3, 2014*

**math**

PV = 25000(1.03)^-28 = $10,926.92 i = .12/4 = .03 n = 7(4) = 28
*June 3, 2014*

**Math**

the above factor of x^3 - 1 factors to (x-1)(x^2 + x + 1) the x-1 = 0 gave us x = 1 x^2 + x + 1 = 0 x = (-1 ±√-3)/2 or x = (-1 ± i√3)/2
*June 3, 2014*

**Math**

5x^4=5x x^4 - x = 0 x(x^3 - 1) = 0 x = 0 or x^3 = 1 x = 0 or x = 1 There are also two complex roots, but I don't think you have studied that. Let me know if you did.
*June 3, 2014*

**math**

second question: How can Frank be a jacket ? third question: What language is this: "what is the fraction of the amount that he that he needs to saved" What does that mean?
*June 3, 2014*

**math 1 question!!!!!!**

Didn't Ms Sue just prove to you that is is C ??
*June 3, 2014*

**correction - math**

subtract them as they sit -y = 4 y = -4 back into the first: x -3(-4) = 25 x + 12 = 25 x = 13 x = 13, y = -4 , you had them opposite.
*June 3, 2014*

**Math**

correct
*June 3, 2014*

**Math**

adults --- x girls ----- 4x boys ------5x (note x: 4x : 5x = 1 : 4 : 5) "6 more boys than girls" ---> 5x = 4x+6 x = 6 so we had 6 adults, 24 girls, and 30 boys, (satisfying all our conditions stated)
*June 3, 2014*

**Math**

nope f(-3) = (-3)^2 - 5(-3) + 1 = 9 + 15 + 1 = 25
*June 3, 2014*

**If 12 people are playing in a tournament and?**

number of subsets of 2 elements from a sample space of 12 = C(12,2) = 66
*June 3, 2014*

**Math**

yes
*June 3, 2014*

**Math**

f(4) = 16+9 = 25 g(-1) = 24-4 = 20 so what is the problem?
*June 3, 2014*

**Math ~ Check Answers ~**

use the first pair of points (2,1) and (4,0) slope = -1/2 so y = mx + b ----> y = -(1/2)x + b sub in (4,0) 0 = (-1/2)(4) + b b = 2 y = (-1/2)x + 2 use our non-used point to check: does (6,-1) lie on it? LS = -1 RS = (-1/2)(6) + 2 = -3+2 = -1 your answer is good.
*June 3, 2014*

**Algebra 1--Please, help me!**

((n-5)/(n^2 - 2n -3)) / ((n-3)/(n^2 -4n - 5)) multiply both sides by (n^2 - 2n -3)(n^2 - 4n - 5) , sometimes called cross-multiplying n^3 - 4n^2 - 5n - 2n^2+ 8n + 10 = n^3 - 2n^2 - 3n - 3n^2 + 6n + 9 -n^2 = -1 n^2 = 1 n = ± 1
*June 3, 2014*

**word problem?**

prob(going to amusement park) = 8/18 = 4/9 so number of the 225 who would go = (4/9)(225) = 100 notice Ms Sue's equation will yield the same answer.
*June 3, 2014*

**Algebra 1**

did that for you here http://www.jiskha.com/display.cgi?id=1401816411 #2, was also done somewhere, can't find it, so ... The way you typed it: 2/t + 4/3t = 4/t + 2 times 3t 6 + 4t^2 = 12 + 6t 4^2 - 6t - 6 = 0 2t^2 - 3t - 3 = 0 t = (3 ± √33)/4 somehow I don'...
*June 3, 2014*

**Scientific notation**

area = (5x10^4)(6x10^3) = 30x10^7 = 3.0 x 10^8 m^2
*June 3, 2014*

**Probability???**

yes, but I would rather have you think of (1/520)(7800) = 7800/520 ---> see, there is your division by 520 = 15
*June 3, 2014*

**Math**

|5m-11| = 9+3m case 1: 5m-11 = 9+3m 2m = 20 m = 10 case 2 -5m + 11 = 9+3m -8m = -2 m = 1/4 product of answers = 10(1/4) = 5/2 oe 2.5
*June 3, 2014*

**Algebra 1--Please, help me!**

let the amount to be added by x ml so we have 300+x ml of the new mixture .3(300+x) = .4(300) 3(300+x) = 4(300) 900 + 3x = 1200 3x = 300 x = 100 Add 100 ml of water check: Do we have the correct amount of acid? in original: .4(300) = 1200 ml in new: .3(400) = 120 ml -----> ...
*June 3, 2014*

**Algebra/can you ck my anwers**

my sum was 1770 divide that by 25 gave me a mean of 70.8 your mean of 1616 should have hit you as absurd. range is correct, your median and mode sound logical
*June 3, 2014*

**Algebra 1--Please, help me!**

#3 no need for all those brackets ... (d + 2)/(d + 8) = (-6)/(d + 8) multiply both sides by (d+8) d+2 = -6 d = -8 ahhh, trick question. Notice in the original, d≠ -8 So there is no solution. #4 correct #5 handled by bobpursley #6 (x -6)/(x^2-6) = (-4)/(x-4) x^2 - 10x + ...
*June 3, 2014*

**Algebra 1 (Reiny)**

Sorry I misread your original question So here is the correct one: right now : amount of orange juice = .25(8) = 2 cups amount of apple juice = .75(8) = 6 cups let the amount of pure orange juice to be added be x cups so just looking at the orange juice: 2 + x = .4(x+8) times ...
*June 3, 2014*

**algebra**

Bosnian was right in his first post. (think I will have a third cup of coffee to wake up)
*June 3, 2014*

**algebra**

sorry, did not register the "linear" part, and concentrated on the "increasing" actually I think it is a), the slope between any two points is 3/2 all points satisfy the equation 3x-2y=7 http://www.wolframalpha.com/input/?i=interpolate+%281%2C-2%29%2C%283%...
*June 3, 2014*

**algebra**

correct http://www.wolframalpha.com/input/?i=plot+%281%2C-3%29%2C%283%2C5%29%2C%285%2C11%29%2C%287%2C18%29
*June 3, 2014*

**statistics**

You have the subtraction backwards A score of 90 is above the mean, so the z-score should be positive z-score = (90-84)/8 = +.75
*June 3, 2014*

**Algebra 1--Please, help me!**

Argggghhh Duplicate question Didn't see that Steve had already answered it
*June 3, 2014*

**Algebra 1--Please, help me!**

cups of orange juice --- x cups of apple --------- 8-x .25x + .75(8-x) = 4.(8) 25x + 75(8-x) = 40(8) I will let you finish it 2. For your type of perfect-square trinomial the first and last terms would have to be positive. ---- the -9 takes this one out of the category. It is ...
*June 3, 2014*

**Algebra 1--Please, check my answer!**

correct
*June 3, 2014*

**Trig**

(320cos120 , 320sin120) + (35cos60 , 35sin60) you should be familiar with the trig ratios of the 30-60-90 triangle, and the multiples of those angles using the CAST rule = (320(-1/2) , 320(√3/2) + (35(1/2) + 35(√3/2) = (-160 , 160√3) + (35/2 , 35√3/2...
*June 2, 2014*

**Algebra**

Your equation doesn't even match your given data length --- x width ---- 2x - 2 area = x(2x-2) = 82 2x^2 - 2x - 82 = 0 x^2 - x - 41 = 0 use the formula ... x = (1 ± √165)/2 = appr 6.92 or some negative length = 6.92 , length = 11.85 check: 6.92x11.85 = appr 82
*June 2, 2014*

**statistics**

Looks like that professor is still giving those A's See the first 3 "Related Questions" below
*June 1, 2014*

**algebra**

let the number of boxes be x 45x + 4000 = 11200 I will let you solve this equation.
*June 1, 2014*

**trigonometry, check please**

I got 10.064.. which to the nearest tenth is 10.1
*June 1, 2014*

**Algebra ll**

hope you got -23 -48
*June 1, 2014*

**trigonometry ans.**

yes, to the nearest foot it is 66 ft
*June 1, 2014*

**trigonometry ans.**

correct in reference to your angle you are involving the opposite and the adjacent side since tanØ = opposite/adjacent your choice of tangent was correct.
*June 1, 2014*

**algebra.can you ck my answers**

216 = 6^3 <-----> log6 216 = 3 How did you ever get 0 as an answer? That is not even an equation ! I suggest you memorize the definition of logs 16-(1/4)^-2 1/2 No idea what that is supposed to be. Was that supposed to be an equation like your question suggested?
*June 1, 2014*

**math**

so the $72.09 represents 70% of the original price .7x = 72.09 x = 72.09/.7 = $102.99 check by taking off 30% of that
*June 1, 2014*

**Math**

you would have 6 equal surface areas 6x^2 = 24 x^2 = 4 x = √4 = 2
*June 1, 2014*

**Math**

length of side of the larger --- x length of side of the smaller -- y x+y = 5 So what do we see? We see 4 side faces of the larger = 4x^2 we see 4 side faces of the smaller = 4y^2 If we look straight down, we see a small face on top of the large face exposing the edge of the ...
*June 1, 2014*

**Math**

Since you already have the second part, let's work on the number of pennies , dimes and quarters we have to make $5.98 number of pennies -- x number of dimes ---- y number of quarters -- 52-x-y x + 10y + 25(52-x-y) = 598 x+10y + 1300 - 25x - 25y = 598 -24x - 15y = -702 8x...
*June 1, 2014*

**Algebra**

amount into lower rate account --- x amount into higher rate account --- 8000-x .04x + .07(8000-x) = 480 4x + 7(8000-x) = 48000 4x + 56000 - 7x = 48000 -3x = -8000 x = 8000/3 = 2666.67 amount into CD = $2666.67
*June 1, 2014*

**Algebra 1**

Since F lies on DE, all we need is the equation of DE We don't even need F slope DE = (-2-2)/(-3-3) = 2/3 so y = (2/3)x + b but (3,2) lies on it, so 2 = (2/3)(3) + b b = 0 y = (2/3) x is the equation check: F is the origin (0,0) which satisfies y = (2/3)x A rather ...
*June 1, 2014*

**Algebra 1**

#1 and #2 ok #3, I agree with you, there is little that can be done All I could see is to divide top and bottom by 2g #4 ok #5, careless error, 2/2p = 1/p , not p #6 you have a common denominator, so add them 8m^2/(4m^5) = 2/m^3 #7, according to BEDMAS, division is done in the...
*May 30, 2014*

**Math**

if arithmetic, then 8 - (5+x) = (1+2x) - 8 8 - 5 - x = 1 + 2x - 8 -3x = -10 x = 10/3 check: terms are 25/3 , 8 , 23/2 or 25/3 , 24/3 , 23/3 which is an AS
*May 29, 2014*

**Math**

Sum(all terms) = a/(1-r) = 200/(1/2) = 400
*May 29, 2014*

**statistics**

Tools like this below replace tables traditionally found at the back of textbooks http://davidmlane.com/hyperstat/z_table.html enter your mean and sd, click on "above" for "exceeds 0.83" and enter the data to get .1587 ,or .159 correct to 3 decimals
*May 29, 2014*

**College Algebra**

Your last one 3/(x-4)=7/(x-8) is the easiest of the three equations just multiply each side by (x-4)(x-8) , which is sometimes called "cross-multiplying" 7(x-4) = 3(x-8) 7x - 28 = 3x - 24 4x = 4 x = 1
*May 28, 2014*

**College Algebra**

z^2 +iz -(5+i) = (2-5i)^2 + i(2-5i) - (5+i) = 4 - 20i + 25i^2 + 2i - 5i^2 - 5 - i = 4 - 20i - 25 + 2i + 5 - 5 - i = -21 - 19i
*May 28, 2014*

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