Friday

July 1, 2016
Total # Posts: 35,112

**Algebra 2**

I have to know more about the spinner. How many colours, etc
*May 18, 2016*

**Algebra**

nope, it is 4 units up Make a table of values of each using the same x's and see what happens http://www.wolframalpha.com/input/?i=plot+y%3D+-6+x%5E2+%2B4+,+y%3D+-6x%5E2
*May 18, 2016*

**alg 2**

the centre of (x - 2)^2 + (y + 1)^2 = 16 is (2,-1) Now move that centre 4 units to the left and 6 units up New centre is ....... new equation is .......
*May 18, 2016*

**Calculus**

a = 1.1+2(t^1/2) v = 1.1t + (2/(3/2)) t^(3/2) + c v = 1.1t + (4/3)t^(3/2) + c when t = 0 , v = 0 0 = 0 + 0 + c -----> c = 0 v = 1.1t + (4/3) t^(3/2) when t = 9 v = 1.1(9) + (4/3) (9)^(3/2) = 9.9 + (4/3)(27) = 9.9 +36 = 45.9 m/h
*May 18, 2016*

**math**

expression "2n+1" is your "number pattern" what do you get when you plug in n = 1, 2, 3, ... ?
*May 18, 2016*

**gscc**

height of cone is 1/2 the diameter ---> height of cone equals its radius V= (1/3)π r^2 h, but r = h V = (1/3) π h^3 dV/dt = π h^2 dh/dt *** dV/dt = 200 cm^3/s so when t = 10 V = 2000 cm^3 2000 = (1/3)π h^3 h^3 = 6000/π h = (6000/π)^(1/3) = appr...
*May 18, 2016*

**math**

4^x = 2^(2x) = (2^x)^2 let y = 2^x , so your equation becomes y^2 - 9y = -20 y^2 - 9y + 20 = 0 (y-4)(y-5) = 0 y = 4 or y = 5 then 2^x = 4 = 2^2 x = 2 or 2^x = 5 take log of both sides, and use log rules x log2 = log5 x = log5/log2 = appr 2.322
*May 18, 2016*

**Math**

20 evens, and 20 odds prob(E,E) = (20/40)(19/39) = 19/78
*May 18, 2016*

**Inequality**

-2 < 7-3x ≤ 10 subtract 7 from everybody -9 < -3x ≤ 3 divide everybody by -3, must switch inequality sign 3 > x ≥ -1 -1 ≤ x < 3 so integral values are {-1, 0, 1, 2}
*May 18, 2016*

**Math**

Wow, I don't see a single one of your answers. How can I possibly check them?
*May 18, 2016*

**Math**

To have the same colour, you need either BBB or RRR Find the prob of each case, then add them up
*May 18, 2016*

**Math**

If passing math depends on this ONE question, and you don't know how to answer this simple question, I don't think you should pass.
*May 18, 2016*

**Math**

prob(at least 1 boy of 4 kids) = 1 - prob(all girls) = 1 - (1/2)^4 = 1 - 1/16 = 15/16
*May 18, 2016*

**Math/Applied**

For the sum to be odd, one choice must be even , the other odd (the sum of two odds is even, the sum of 2 evens is even) We have 5 odds and 4 evens in the bag so 2 cases: prob(E, then O) = (4/9)(5/8) = 20/72 = 5/18 prob(O, then E) = (5/9)(4/8) = 5/18 prob(your event) = 5/18+5/...
*May 18, 2016*

**Math**

missing 3 times out of how many tries?? if prob(miss out of 3 tries) = (1/10)^3 = 1/1000
*May 18, 2016*

**Math**

looks like somebody has some major studying ahead of them
*May 18, 2016*

**Math**

I copied your post with only those that are INCORRECT I am using <-------- to show the correct answer 1. Simplify. 3x^2+ 5x-5x^2-4x+5-2 A.-8x^2-9x+3 B.2x^2+x+3 C.-2x^2-9x+3*** D.-2x^2+x+3 <--------- 4.The distance from Newtown to Old town on the highway is (6x^2 + 2x &#...
*May 18, 2016*

**Math**

Any reason why you are capitalizing every word? Assuming your garbled last sentence is something like: "If one of the sides of the first triangle is 6 cm, what is the length of the corresponding side of the second triangle ? " Areas of similar triangles are ...
*May 18, 2016*

**Differential Calculus**

Make a sketch of the cone with some water in it. Let the depth of the water be h ft, and the radius of the water level be r ft by similar triangles: r/h = 3.75/15 3.75h = 15r h = 4r or r = h/4 V = (1/3)π r^2 h V = (1/3)π(h^2/16)h V = (1/48)π h^3 dV/dt = (1/16)&#...
*May 18, 2016*

**Calculus**

take the 2nd derivative, set it equal to zero and solve for x that will be the x value of the inflection point, sub it back into the original equation to get the y your second derivative will be a linear expression, thus easy to solve for x
*May 18, 2016*

**Math**

you have 6 pizzas, and you slice each one of them into 5 pieces. How many pieces will there be in total ?
*May 18, 2016*

**math**

Find the area of the rectangle. Find the area of the circle take the difference between the two answers.
*May 18, 2016*

**financial management**

i = .16/12 = .013333... p(1 - (1.013333..)^-12)/.01333.. = 250000 solve for p , where p is the monthly installment
*May 18, 2016*

**Math**

area of parallogram = base x heigh = 6.5(4.8) = .. new dimension: base = 13 height = 6.3 new area = 13(6.3) = .... take the difference
*May 17, 2016*

**Algebra**

y = kx plug in the given values of x and y, then solve for k rewrite the original equation, now that you know k
*May 17, 2016*

**math**

(1/2)(l) = 2/3 l = (2/3) ÷ (1/2)
*May 17, 2016*

**math**

(sum of 4 tests + x)/5 = 77
*May 17, 2016*

**Math3(Reiny Please Help)**

h(t) - -9.81t^2 + 0t + h = 0 when it hits the ground when t = 3.5 -9.81(3.5)^2 + h =0 h = 120.1758 m b) repeat for the equation h(t) = -9.81t^2 -5t + 120.1725 set that equal to 0 and solve for t , reject any negative values of t
*May 17, 2016*

**Math2(Reiny Please Help)**

set 0.02(3s^2 + 20s) = 50 3s^2 + 20s = 2500 3s^2 + 20s - 2500 = 0 Use the quadratic formula, reject the negative answer.
*May 17, 2016*

**Math(Reiny Please Help)**

let the width against the barn be x ft let the length parallel to the barn be y ft so total length = 600/15 = 40 so she needs to fence 40 ft 2x + y = 40 y = 40-2x area =xy = x(40-2x) = 40x - 2x^2 are you taking Calculus? if so, d(area)/dx = 40 - 4x = 0 for a max of area x = 10...
*May 17, 2016*

**Math**

a) number greater than 9: 10,11,12,13,14,15 so 6 of them prob(as stated) = 9/15 = 3/5 b) do it the same way, count how many are prime, and how many are composite
*May 17, 2016*

**Math**

areas of similar figures are proportional to the square of their corresponding sides so the larger one is 9 times as large, or 243 m^2 or, if you didn't know that property let the original be (1/2)(base)(height) = 27 new one is (1/2) (3base)(3height) = 9 (1/2)(base)(height...
*May 17, 2016*

**MATH**

of course! you must have the same units 12/9 would be a meaningless calculation. 36 ft ÷ (9/12) ft = 48 Now, the question is not clear about posts at the end. e.g. If the fence has one side along a house, would you need a post right against the house at each end? If so ...
*May 17, 2016*

**math**

term5 = a+4d term2 = a+d a+4d = 2(a+d) a+4d = 2a + 2d a = 2d sum(20) = 10(2a + 19d) = 1150 2a + 19d = 115 4d+19d=115 23d = 115 d = 5 a = 10 you MUST know how to do this simple kind of question. Repeat the solution on your own, without looking at mine. Practise, practise, ...
*May 17, 2016*

**math**

volume of well = π r^2 h = π(7^2)(20) = 98π m^3 surface area to be covered by dirt = 100(42) - π(7^2) =4200 - 49π m^2 let the depth of the dirt be h m (4200 - 49π)h = 98π check and do my arithmetic
*May 17, 2016*

**Math**

What is your choice ?
*May 17, 2016*

**Math**

If expressed in terms of y ... 4y = 2x y = (2/4)x = (1/2)x so yes, with k = 1/2
*May 17, 2016*

**Math/algebra**

- find the mean - take the difference between each of your data values and the mean - square each of these differences - add up these squares of differences - divide by 10 - take the square root I will not do the arithmetic of that for you
*May 17, 2016*

**Math/algebra**

you have a GP, with a = -2, r = -2 term(20) = a r^19 = -2(-2)^19 = (-2)^20 = 2^20 = 1,048,576
*May 17, 2016*

**Math Help Please I Don't Understand**

you have to be familiar with the meaning of the constants in an equation such as y = a sin k(Ø+d) + c a is the amplitude, our range of heights is 60 ft so a = 30 y = 30sin kt + c , where t is in minutes the lowest value so far would be -30, but we need our lowest to be...
*May 17, 2016*

**Geometry**

So you want them to be an arithmetic sequence 19 , 19+d, 19+2d, 19+3d but 19+3d = 55 3d= 36 d = 12 etc
*May 17, 2016*

**MATH**

Let the width be w area of first = 12w area of 2nd = 8w 12w - 8w = 320 carry on
*May 17, 2016*

**math**

I noticed that Steve answered this for you 20 minutes ago. Why are you repeating it ?
*May 17, 2016*

**Algebra**

The way you typed it, it would be undefined for x = 0 if you meant: (x+1)(x-2)/(x^2-25) then it would be undefined for x = ± 5
*May 16, 2016*

**Algebra**

so your height formula is h = -4.9t^2 + 4.9t + 0 , assuming kicked from ground when it lands, h = 0 -4.9t^2 + 4.9t = 0 -4.9t(t - 1) = 0 t = 0 ----> at the moment the ball is kicked or t = 1, it lands 1 second later
*May 16, 2016*

**Finance**

This is a normal amount of annuity problem payment = 650 i = .078/4 = .0195 n = 4(5) = 20 amount = 650 ( 1.0195^20 - 1)/.0195 = $15,714.90
*May 16, 2016*

**math**

you will be in the 4th quadrant, 39° down from the x-axis cos 39° = x/800 x = 800cos39 = 621.7 m east y = 800sin39 = 503.5 m south notice : 621.7^2 + 503.5^2 = 639979.1489 √639979.1489 = 799.987 , not bad
*May 16, 2016*

**Math**

y^2 + 9y + 9 = 0 straightforward quadratic equation, unfortunately it does not factor, so .... by the formula y = (-9 ± √45)/2
*May 16, 2016*

**Math(Reiny Could You Help?)**

the vertex of f(x) is (2,9) The vertex of g(x) is to the right 2 units and 5 units down, so its vertex must be (4,4) since the "shape" has to be the same, we need the same 3 in front so g(x) = 3(x-4)^2 + 4 domain: the set of real numbers range: y ≥ 4 , since ...
*May 16, 2016*

**Math**

golf balls ---- 20x tennis balls -- 5x 20x+5x = 100 25x = 100 x = 4 so 80 golf balls and 20 tennis balls
*May 16, 2016*

**Geometry**

slope of AB = (4+8)/(-9+7) = 12/-2 = -6 so the slope of the perpendicular = 1/6 midpoint of AB = (-8,-2) equation of our line: y + 2 = (1/6)(x+8) 6y + 12 = x+8 x - 6y = 4
*May 16, 2016*

**math**

We clearly need a diagram to know what you are talking about. Since we cannot post diagrams here, ......
*May 16, 2016*

**Math**

your function is modelled by a parabola which opens downwards. when the package reaches the water, h(t) = 0 -4.9t^2 + 10t + 1200 = 0 t = (-10 ± √23620)/-9.8 = -14.662 or 16.7029 We will reject the negative time, so it took appr 16.7 seconds for the package to ...
*May 16, 2016*

**Math (Trig)**

you know that the point is in quad II and tanØ = 2/-1 I know that for tanØ= +2, Ø = appr 1.107 so our angle in II is Ø = π-1.107 = 2.0344 so it has to be (5, 2.0344) if you use the form (r,Ø)
*May 16, 2016*

**Math**

I don't like the wording "repeatedly" Usually this type of question uses "continuously" to describe the increase. amount = a e^(kt) , where k is the annual rate , t is the time in years and a is the initial amount. e^(k(9.25)) = 2 take ln of both sides ...
*May 16, 2016*

**math**

A not-so-subtle way to promote two wineries??
*May 16, 2016*

**Calculus**

We need their intersection: 2x^2 - 2 = x^2 + 1 x^2 = 3 x = ± √3 we want only the part in the first quadrant effective height = x^2 + 1 - (2x^2 - 2) = 3 - x^2 area = ∫(3 - x^2) dx from 0 to √3 = [3x - (1/3)x^3] from 0 to √3 = 3√3 - (1/3)(3&#...
*May 16, 2016*

**Math**

h(t) = -4sin (π/4)(t-1)+2.5 The period of this function is 2π/(π/4) = 8 So we want to see where the sine curve falls below the x-axis for 3 periods of the curve, starting at t=0 0 = -4sin (π/4)(t-1)+2.5 4sin (π/4)(t-1) = 2.5 sin (π/4)(t-1) = .625 ...
*May 16, 2016*

**math**

f+k = 1548 f+j = 1842 subtract those two equations: j-k = 294 j = 294 + k k/j = 4/7 4j = 7k j = 7k/4 sub into j = 294+k 7k/4 = 294 + k times 4 7k = 1176 + 4k 3k=1176 k = 392 then j = (7/4)(392) = 686 f+j = 1842 f = 1156
*May 16, 2016*

**math**

227.5( 1- (1+i)^-60)/i = 9500 You will need some "fancy" methods to solve this type of an equation, e.g. Newton's Method I just ran it through Wolfram and got i = .0127495 for a monthly rate or an annual rate of appr . .152994 or appr 15.3% per annum compounded ...
*May 16, 2016*

**Statistics**

I assumed you know how to find the mean and sd for the given information.
*May 15, 2016*

**Statistics**

straightforward .... find z scores for both 12 and 14 minutes go to the chart, look up the two z-scores proabilities, then subtract them
*May 15, 2016*

**Math Help**

The two questions are very similar in setup, I will do the first one, you do the second length = integral √( 1 + (y')^2) dx from a to b yours: y = (2/3)x^(3/2) + 2 y' = x^(1/2) (y')^2= x length = integral √( 1 + x) dx from 14 to 16 = [ (2/3)(1+x)^(3/2...
*May 15, 2016*

**Math**

5x - 3 = 7x + 11 x=-4 <------------ No 5x-7x = 11+3 -2x = 14 x = -7 3w -4 = w+8 w =6 < --------- Yes
*May 15, 2016*

**Algebra**

Just add the "like" terms
*May 15, 2016*

**Math**

times 3 , the LCD b-4 = 3 take over
*May 15, 2016*

**Integral calculus**

We are rotating a circle with centre at (3,0) and radius 3 around the y-axis Because of symmetry we can use the part only above the x-axis, then double it. see Khan for a nice explanation of the shell method https://www.khanacademy.org/math/integral-calculus/solid-revolution-...
*May 15, 2016*

**Percent**

what is 46/1.15 ?
*May 15, 2016*

**Math**

15,590(1.05)^n = 55,433 , where n is the number of years 1.05^n = 3.55567.. (I stored it in memory) take logs of both sides nlog 1.05 = log 3.55567.. n = 26.00002.. I would say she owned it 26 years
*May 15, 2016*

**Algebra**

What's with the 8_/8 ?? We solve equations, I don't see an equation. If you are evaluating (3/8)(2/6) = 6/48 = 1/8
*May 15, 2016*

**math**

r = 17y so area = π(17y)^2 = 289y^2 π
*May 15, 2016*

**algebra/trigonometry**

Didn't that answer strike you as totally unreasonable? How can the kite-string be only 1 cm long ?? Steve told you : 75/x = sin 60° so x sin60 = 75 x = 75/sin60 = appr 86.6 metres
*May 15, 2016*

**Math**

Final bill = $97.38(.65)(1.18) = $74.69 share of each friend = 74.69/4 = $18.67
*May 15, 2016*

**Maths**

Come on folks, this is silly. 4:37 + 2:48 = 277 minutes + 168 minutes = 445 minutes = 7 hours and 25 minutes or 7:25 If you have a scientific calculator, look for a key like D°M'S Use it for either adding/subtracting time or angles in degrees. enter 4 D°M'S 37...
*May 15, 2016*

**math**

all 4 angles have to add up to 360°, so x + x+10 + x+20 + x+30 = 360 solve for x, then sub into the angle expressions
*May 15, 2016*

**math (PLZ HELP ASAP)**

teacher's age --- x son's age ---- y x-2 = 3y x = 3y+2 x-7 = 2(y+2) 3y + 2 - 7 = 2y + 4 y = 9 x= 3(9)+2 = 29
*May 14, 2016*

**math**

Assuming you meant: 480 - 8t - .8t^2 or R1 sub in all the values of t into R1, then add them up sub in all the values of t into R2, then add them up compare the two answers.
*May 14, 2016*

**math**

"that no one even out of the 4 balls being white" ?? you mean, none of the balls drawn is white ? 8 of the 12 are "non-white" prob(of your event) = (8/12)(7/11)(6/10)(5/9) = 14/99 assuming the balls are not returned after they are drawn
*May 14, 2016*

**Maths fractions**

Let c be the capacity of the tank (1/5)x + 700 = (2/3)x times 15, the LCD 3x + 10500 =10x 7x=10500 x = 1500 The tank holds 1500 ml or 1.5 L
*May 14, 2016*

**Functions Math**

After 3 hours of driving, there are 10 gallons left.
*May 14, 2016*

**Math**

amount = 3000(2)^(t/2) , where t is the number of days = 3000(2)^(15/2) = 543,058 How did you get 45,000 ?
*May 14, 2016*

**Algebra**

1+1.1p - (1.5p - 1) = 4 1 + 1.1p - 1.5p + 1 = 4 -.4p = 2 p = - 5 check: 1.5(-5) - 1 = -8.8 1+1.1(-5) = -4.5 their difference is 4
*May 14, 2016*

**Algebra**

really the same question as this one: http://www.jiskha.com/display.cgi?id=1463240595 Just change the numbers
*May 14, 2016*

**Math**

3(5x+5) - 2 = 0 15x + 15 - 2 = 0 15x = -13 x = -13/15 check: g(-13/15) = 5(-13/15) + 5 = 2/3 f(2/3) = 3(2/3) - 2 = 2-2 = 0 my answer is correct
*May 14, 2016*

**math**

266 2/3% = 800/3 % = 800/300 = 8/3 so (8/3)x = .6 x = 1.8/8 = .225
*May 14, 2016*

**Algebra**

#1, ok #2, y varies inversely with x ---> y = k/x given: if y=2, x=8 2 = k/8 k = 16 so y = 16/x <------- D
*May 13, 2016*

**Geometry**

let the slant height be s s^2 = 8^2 + 37^2 s = 37.8549.. Lateral surface area = πrs = π(8)(37.8549..) = appr 9514 , none of the given choices if we include the circular base of 201.062 we get appr 1152 m^2
*May 13, 2016*

**Math**

This question was answered here, why are you repeating it ? http://www.jiskha.com/display.cgi?id=1463122066
*May 13, 2016*

**Math**

Why did you switch names? http://www.jiskha.com/display.cgi?id=1463155297
*May 13, 2016*

**Math**

I suspect you are missing a term and it should be like this. (or else not much will cancel) [(x^2 + 2x + 1)/(x^2 - 8x + 16) ] / [(x+1)/(x62-16) ] = [(x+1)(x+1)/(x-4)(x-4)) ]/[ (x+1)/(x-4)(x+4) ] = (x+1)(x+1)/(x-4)(x-4)) * (x-4)(x+4)/(x+1) = (x+1)(x+4)/(x-4)
*May 13, 2016*

**Math**

look at Steve' solution to the same question: http://www.jiskha.com/display.cgi?id=1367836044
*May 13, 2016*

**maths**

I don't see your choice of answer? Did you forget it?
*May 13, 2016*

**Algebra**

Your time of 3.75 seconds is correct. Now sub that into the original equation for h I certainly did not get 7.58
*May 13, 2016*

**geometry**

excuse me, but I spent considerable time doing this for you yesterday http://www.jiskha.com/display.cgi?id=1463065994 Why are you posting it the same way without altering any of the parts I questioned? What part of my answers did you not like ?
*May 13, 2016*

**math**

#1, #2 are correct #3 - #9 need a look at the diagrams, which of course we can't post here #10 - #12 look good #13 ----- need diagram, can't tell which numbers go where #14 --- need diagram #15 , I guessed what you meant, looks ok #16 18/15 = x/5 15x = 90 x = 6 #17 ...
*May 12, 2016*

**Math/Precal**

According to your wording, a digit cannot be used more than once. I stand by my answer .
*May 12, 2016*

**Math/Precal**

the first digit has to be either a 4,5,6, or 7 number of cases = 4 x 9 x 8 x 7 = 2016
*May 12, 2016*

**Math**

you want 2 from the 5 boys, and 3 from the 6 girsl number of selections = C(5,2) x C(6,3) = .......
*May 12, 2016*

**Math**

Is this a follow up from your previous question? term(3) = ar^2 = 20 a = 20/r^2 a/(1-r) = 3a 1/(1-r) = 3 same as in your previous post, r = 2/3 then a = 20/(4/9( = 20(9/4) = 45 test: your sequence is 45 , 30 , 20 , 40/3 , 80/9 , ... is the third term 20 ? , YES sum of all ...
*May 12, 2016*

**Math**

a/(1-r) = 3a divide by a 1/(1-r) = 3 1 = 3 - 3r 3r = 2 r = 2/3 plug in r = 2/3 a/(1 - 2/3) = 3a a/(1/3) = 3a 3a = 3a , which is a true statement, so "a" can be anything. But in a GP, the first term cannot be zero so the first term can be any real number except zero.
*May 12, 2016*