Saturday

April 19, 2014

April 19, 2014

Total # Posts: 26,024

**Math - Quart to Gallon Ratio**

2.5 gallons = 320 oz punch : grape juice = 64 : 16 = 320 : g 64/16 = 320/g 4 = 320/g 4g = 320 g = 80 it would take 80 oz of grape juice number of quarts = 80/32 = 2.5 quarts (Editorial: Go metric to avoid such silly calculations)

**math**

original perimeter = 2L + 2w new length = 2L new width = 3W new perimeter = 4L + 6w 4L+6w - (2L+2w) = 92 2L + 4w = 92 L + 2w = 46 L = 46-2w area of original = lw = w(46-2w) = 46w - 2w^2

**math**

children tickets ---- x adult tickets ------- 3x 9x + 5.3(3x) = 872.10 take over from here

**math**

3hex + 4trap = 200 3hex = 200 - 4trap 1 hex = (200-4trap)/3 or 4trap = 200 - 3hex 1 trap = (200 - 3hex)/4

**Math Pre-Cal**

to know the "value" of the quadratic function, you must know the value of x simply plug in your given value of x and work it out.

**Math Pre-Cal**

Use the vertex form first y = a(x-h)^2 + k, where (h, k) is the vertex, so ... vertex is (1,-1) so f(x) = a(x-1)^1 - 1 but (2,2) lies on it, so 2 = a(2-1)^2 - 1 2 = a(1) - 1 3 = a so you have f(x) = 3(x-1)^2 - 1 now expand this ... f(x) = 3(x^2 - 2x + 1) - 1 = 3x^2 - 6x + 3 - ...

**Math**

let the height be h h^2 + 12^2 + 4^2 = 14^2 h^2 + 144 + 16 = 196 h^2= 36 h = √36 = 6

**pre cal**

mmmhhh? (0+3)^2 = 3^2 = 9

**pre cal**

Look back at my explanation in the previous post for vertex (h,k), we get y = a(x-h)^2 + k so for vertex (-3,5), we get y = a(x-(-3) )^2 + 5 or y = a(x + 3)^2 + 5 Now plug in the other point (0, -4) -4 = a(0+3)^2 + 5 -4 = a(9) + 5 -9 = 9a a = -1 y = -(x+3)^2 + 5

**pre cal**

Two points only is not enough to establish a quadratic, unless one of those points is the vertex. If one of the points is a vertex, use the method I just showed you in your previous post. Let me know what you think.

**Math help**

Well,you are told that y has a value of 3 so in the 2nd equation, simply replace y with that value and solve for x 4(3) = 2x + 18 12 - 18 = 2x -6 = 2x -3 = x so x=-3, y = 3 Done!

**Math**

taking a stab at .75

**Pre cal**

in your text or in your notes, you should have the usual form of the equation if you have the vertex if vertex is (h, k) then the equation of the quadratic is y = a(x-h)^2 + k compare the values of (h,k) with your vertex of (3,-13) the value of a govern which way the parabola ...

**Pre cal**

Since you are using the word "vertex" I will assume you might be talking about a quadratic function. with vertex (3,-13) the parabola would be y = a(x-3)^2 -13 but (0,-4) lies on it, so .... -4 = a(9) - 13 9a = 9 a = 1 f(x) = (x-3)^2 - 13

**Algebra**

yes, you are correct example of exponential growth graph http://www.wolframalpha.com/input/?i=plot+y+%3D+2%5Ex example of exponential decay graph http://www.wolframalpha.com/input/?i=plot+y+%3D+%281%2F2%29%5Ex

**Math**

Let the number be x 2(x-2) + 7 = 57 2x - 4 = 50 2x = 54 x = 27

**math**

MN = √( (11-3)^2 + (-2+4)^2 ) = √(64 + 4) = √68 or 2√17

**Calculus**

smaller number --- x larger number ----- x + 132 product=P=x(x+132) = x^2 + 132x dP/dx = 2x + 132 =0 for a min of P 2x = -132 x = -66 the smaller is -66 the larger -66+132 or +66 the two numbers are -66 and +66

**Calculus**

let the sides of the base be x cm each let the height be y V= x^2 y 4000/x^2 = y surface area = x^2 + 4xy = x^2 + 4x(4000/x^2 = x^2 + 16000/x d(surface area)/dx = 2x - 16000/x^2 = 0 for a min surface area 2x = 16000/x^2 x^3 = 16000 x = appr 25.2 cm y = 4000/25.2^2 = appr 6.3 cm

**math**

follow my method in your previous post, let me know what you got

**math**

The way you typed it .... multiply each term by 5x the LCD 8 + 4x = 12x^2 - 13x 12x^2 - 17x - 8 = 0 use the quadratic formula to find 2 answers what you probably meant: 8/(x+4) = 12/(5x-13) 40x - 104 = 12x + 48 28x = 152 x = 152/28 = 38/7

**math**

total number of fish --- x use a simple ratio: x/100 = 400/12 x = 100(400/12) = appr 3333 fish

**math**

How about 6 ?

**math**

Wow,, that must be some school! number of times around = 330/5.5 = 60 times

**math**

it usually takes two steps, 1. "move" all terms except the y term to the right side ---> -y = -7x + 7 2. divide each term by the coefficient of the y term ---> divide by -1 y = 7x - 7 #2. 15x + 3y + 2 = 9x + 14 - try it using my 2-step method

**algebra 1**

So he wants the area to be 4(12) or 48 inches^2 πr^2 = 48 r^2 = 48/π r = appr 3.9 inches

**math**

10 cm:1mm = 100 mm : 1 mm = 100 : 1

**mAtHS**

|4x-3| < 1 4x-3< 1 and -4x + 3< 1 4x < 4 and -4x< -2 x < 1 and x > 1/2 1/2 < x < 1 , that is, x has to be between 1/2 and 1

**density and pressure**

volume = (5)(8)(10) m^3 = 400 m^3 mass = (1.3 kg/m^3)(400 m^3) = 520 kg

**maths**

smaller ---- x larger ------x+5 x + x+5 = 39 continue...

**maths**

the number --- x its reciprocal --- 1/x x + 4(1/x) = 5 times x x^2 + 4 = 5x x^2-5x + 4 = 0 (x-1)(x-4) = 0 x = 1 or x = 4 I leave it up to you to check them out.

**math**

area of ||gm = base x height base (6 5/8) = 26.5 (53/8)base = 26.5 base = 26.5(8/53) = 4 chec: 4(6.625) = 26.5

**Math**

the complement of 55.1° is 34.9° the supplement of 55.1° is 124.9° I cannot comprehend your answer.

**Algebra**

yes

**math**

yes, You can always check your factored answer by simply expanding it. You must get back the original.

**Algebra 1~ For Reiny or Steve, I only have 5 min.**

#1 change 3x+12y=20 12y = -3x + 20 y = (-3/12) + 20/12 y = (-1/4)x + 5/3 same slope, but different y-intercepts, so 2 parallel lines, NO solution #2 Jack = 55 + 4x Emily = 28 + 13x when is 13x + 28 = 4x + 55 13x - 4x = 55 - 28 9x = 27 x = 3 you are right! #3 10x-2 = -7x + 3 17...

**Writing and solving equations**

Just translate the English to Math, after all, Math is just a language. let the number of green balls be g , as suggested "The number of red balls is 3 more than the number of green balls" ---> reds = g+3 "the number of blue balls is 7 more that the number of...

**math**

let the remaining two angles be 16x and 19x 16x+19x+88+62 = 360 ok, up to you...

**Algebra Check**

yup!

**Math**

22 > 2x by 14 22 = 2x + 14 8 = 2x x = 4

**Algebra 1**

slope of first line = -4/5 for the 2nd: -5y = -4x - 15 y = (-4/-5)x - 15/-5 y = (4/5)x + 3 ---> slope is +4/5 so they are neither parallel nor perpendicular. (to be perpendicular, they must be opposite in sign, and flips of each other, not true in your case) 2nd question: s...

**math**

sam would earn (60+89+83+99+95+60)/6 = ... And why would this not be "fair" ???

**Algebra 1**

no remember it is y - y1 = m(x-x1) so for (-4,6) y-6 = (2/4)(x - (-4) ) y - 6 = (3/4)(x + 4)

**maths**

number of 20 cent coins ---- 4x number of 50 cent coins ---- 3x (notice 4x : 3x = 4 : 3) 20 of the twenty cents coins were taken out so we have 4x - 20 left value of those 20 coins = 20(20) = 400 cents which would make 400/50 or 8 fifty cent pieces So number of 50 cent coins =...

**Algebra 1**

you got it

**Algebra 1**

-7-(-12) = 5 -2 - (-7) = 5 3 - (-2) = 5 yup, it is! you tell me what the common difference is.

**Math help**

I assume you have a typo, and the 2nd equation is -14x + 4y = 26 notice dividing by 2 will yield the first equation so you basically have ONE equation in TWO unknowns, which will yield an infinite number of solutions, e.g. (1, 10) is one, so is (13, 52) etc

**Typo alert:math---help! 1 question**

my first two lines should have said: 2x + 6 = 2(x+3) 2x+6 = 2x+6

**math---help! 1 question**

3x + 6 = 2(x+3) 3x+6 = 2x+6 0=0 The variable dropped out and we had a true statement. So there will be an infinite number of solutions since the equation is actually an identity, that is, the left side is equal to the right side If , however, the variable drops out, and you en...

**Math**

let the two unknown angles be 3x and 5x 3x + 5x + 100 = 180 ...... take over

**Math - Ratio or Proportion (I think??)**

6 lbs for 3 people for 5 days, then 2 lbs for 1 person for 5 days, or 2/5 lbs for 1 person for 1 day, or 2 lbs for 5 people for 1 day, or 14 lbs for 5 people for 7 days.

**math**

amount of 20% solution to be used: x ounce amound of 50% solution to be used : 60-x .2x + .5(60-x) = .3(60) time 10 2x + 5(60-x) = 3(60) 2x + 300 - 5x = 180 -3x = -120 x = 40 40 ounce of the 20% and 20 ounces of the 50% solution should be mixed.

**Algebra**

correct

**Algebra, URGENT!! HELP!**

(12x^9)^2 = 144x^18

**Math**

let number of miles be x when is .5x + 25 = .25x + 30 times 4 2x + 100 = x + 120 x = 20 equal at 20 miles

**Calculus**

I noticed the following ... A denominator, whose derivative shows up in the numberator... Ahhh, logs! ∫ sin t/(2-cost) dt = ln (2-cost) take it from there.

**Calculus**

by "inspection" I get (1/6)(1 - cos 3t)^2 | from 0 to π/6 = (1/6)(1 - 0)^2 - (1/6)(1 - 1)^2 = 1/6 - 0 = 1/6 I was assuming that your limit went from 0 to π/6

**maths**

x^1 + 1/4 ÷ x^1/4 or (x^1 +1)/4 ÷ x^(1/4) etc ?? must use brackets to establish correct order of operation.

**MATH**

Let the number of students be x number of nuggets = 5x + 30 or number of nuggets = 6x + 4 6x+4 = 5x+30 x = 26 There were 26 students, so she neede 26(5) + 30 or 160 nuggets.

**Math**

Let the side parallel to the house by y the each of the other two sides be x Make a sketch 2x + y = 50 y = 50-2x area = xy = x(50-2x) =50x - 2x^2 the x of the vertex of this parabola is -b/(2a) = -50/-4 = 12.5 so x = 12.5 and y = 50-25 = 25 The garden should be 25 m long and 1...

**MATH**

let number of Chinese books be 3x let the number of English books be 5x number of Malay books = (5/9)(3x) = (5/3)x Malay books : English books = (5/3)x : 5x = 5x : 15x = 5 : 15 = 1 : 3

**algebra**

S = k(T)^(2/5) when S = 8 , T = 32 8 = k (32)^(2/5) 8 = k(4) k = 2 when T = 243 S = 2(243)^(2/5) = 2(3^2) = 18

**Math**

let the number of $25 increases be n rent = 940 + 25n number rented = 218-5n income = (940+25n)(218-5n) = 204920 +750n - 125n^2 If you know Calculus: d(income) = 750 - 250n = 0 for a max of income 250n=750 n = 3 if you don't know Calc complete the square: -125(n^2 - 6n + 9...

**Algebra**

slope = (-9+3)/(-6+2) = -6/-4 = 3/2 y+3 = (3/2)(x+2) 2y + 6 = 3x + 6 3x - 2y = 0

**math(CHECK ASNWERS)**

all ok

**maths**

"Solving" implies you have an equation. You have no equation.

**SAT prep help**

x^4 = 10 x = 10^(1/4) then x^6 = (10^(1/4) )^6 = 10^(3/2) or appr 31.623

**calculus**

You are right, I subbed 10 into the wrong variable Good catch. when y = 10 x^2+ 6^2 = 10^2 x^2 =100-36= 64 x = √64 = 8 in my #1 from above post: 2(8) dx/dt = 2(10)(40) dx/dt = 50 mph

**Algebra**

Ford rental: cost = 35 + .14x, where x is the number of miles Chevy rental: cost = 34 + .16x when is 34 + .16x > 35 + .14x .02x > 1 x > 1/.02 x > 50

**calculus**

Let his horizontal distance over the high school be x let the distance between him and the school be y I see a right-angled triangle and x^2 + 6^2 = y^2 2x dx/dt + 0 = 2y dy/dt , #1 when x = 10, y^2 = 100 + 36, y = √136 in equation #1 2(10) dx/dt = 2(√136) (40) dx/...

**Algebra 2**

x^2 + x = -c x^2 + x + 1/4 = 1/4-c (x+1/2)^2 = (1-4c)/4 x+1/2 = ± √(1-4c)/2 x = -1/2 ± √(1-4c) = (-1 ± √(1-4c) )/2 -keep only the x^2 and x terms on the left - take half of the coefficient of the x term, then square it - add that result t...

**Calc I**

f ' (x) = e^x - 5x^4 f '' (x) = e^x - 20x^3

**Math help**

for all 3 , elimination looks like the easiest way 1. -7x-6y=-21 -x-6y=-3 subtract them to eliminate the y's -6x = -18 x = 3 back into the 2nd: -3-6y=-3 -6y=0 y = 0 ----------> x = 3, y = 0 2. -7x+2y=13 -14x+4y=26 Did you notice that the 2nd equation is simply twice the...

**Calculus**

area = ∫e^(-x/2) dx from x = -6 to ∞ = [-2 e^(-x/2) ] from -6 to ∞ = 0 - (-2e^3) = 2e^3 note: as x ---> ∞ , e^(-huge) = 1/e^huge ---> 0

**PreCAL**

You are right Bosnian, it is D Time to clean my glasses, lol

**PreCAL**

x = 9t+2 --> t = (x-2)/9 y = -6t+9 --> t = (9-y)/6 then : (x-2)/9 = (9-y)/6 6x-12 = 81-9y 9y = -6x + 93 y = (-2/3)x + 31/3 looks like B)

**trig**

forgot to mention that you cannot just skip the "angle" after a trig operator. What you typed would be like having an equation of the type ... √ = ∫ + ∑

**trig**

LS = (csc^2 Ø + cot^2 Ø)(csc^2 Ø - cot^2 Ø = (1 + cot^2 Ø + cot^2 Ø)(1+cot^2 Ø - cot^2 Ø = 1 + 2cot^2 Ø RS = (1 + cos^2 Ø)/sin^2 Ø = (sin^2 Ø + cos^2 Ø + cos^2 Ø)/sin^2 Ø =...

**math**

height after 1st bounce = 10(.6) height after 2nd bounce = (10(.6))(.6) = 10(.6^2) height after 3rd bounce = 10(.6^3) ... height after nth bounce = 10(.6^n)

**MATH**

MMMhhh? Both I and bobpursley answered you . http://www.jiskha.com/display.cgi?id=1390567139 Why are you reposting?

**algebra**

Both Steve and I both answered you in 2 different posts. Do you not look at your earlier posts?

**math**

You must learn to "translate" the English into Math "The product of a number and 2 has the same value as that number minus 2" - product means multiply - a number --- x so far: (x)(2) or 2x - has the same value ---> = so far: 2x = - that number minus 2 --...

**math**

do it the same way I just showed you in your last post Let me know what you think.

**math**

x+0 = x^2 x^2 - x = 0 x(x-1) = 0 x = 0 or x = 1, but x was to be a non-zero integer so x = 1

**Math**

Since no restriction in terms of being a smoker or non-smoker is required, we are simply choosing 5 people from 15 which is C(15,5) = 3003

**Trig**

of course

**Trig**

Why are you calling this trig ? x^2 - 4x + 2 = x+2 x^2 - 5x = 0 x(x-5) = 0 x = 0 or x = 5 sub in those x's in either of the two equations to find the y, then choose your answer. http://www.wolframalpha.com/input/?i=plot+y+%3D+x%5E2+–+4x+%2B+2%2C++y+%3D+x+%2B+2

**Math**

PV = 1333.28(1 - 1.05375^-40)/.05375 = $21750.00 Balance after 8.5 year = 21750.00(1.05375)^17 - 1333.28(1.05375^17 - 1/.05375 = $17365.12 check my arithmetic

**math**

r^10 s^5

**german**

Wir haben geschlafen. (past tense)

**math**

length = 8-2x width = 2-2x height = x volume = x(8-2x)(2-2x)

**8th grade math**

volume = length x width x height = ....

**To: Reiny**

A very confusing question. Are the triangles right-angled? "The slope side of triangle A is double the slope of B" ---> a triangle has 3 sides, what does "slope side" mean? the slope of which side? What is triangle A and what is triangle B.

**Algebra 2**

7n = n - 5n^2 - 20n 5n^2 + 26n = 0 n(5n + 26) = 0 n = 0 or n = -26/5

**To: Reiny**

what question?

**permutation and combination**

so we only use 24 cards, of which 12 are red number of 5-card hands = C(24,5) = 42504 let's exclude number with no reds and only one red number with no reds = C(12,0) x C(12,5) = 792 number with 1 red = C(12,1) x C(12,4) = 5940 no number with at least two reds = 42504 - 79...

**math**

let the width be w length = 2w-5 w(2w-5) = 25 2w^2 - 5w - 25 = 0 (2w+5)(x-5) = 0 w = -5/2 or w = 5, but the width could not be negative, so the width is 5 and the length is 2(5)-5 or 5 your rectangle is a square.

**math**

done before, look back

**Math!**

35/26.25 = 8/h 35h = 8(26.5) h = .....

**math**

16^(1/3) e^4

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