Tuesday

September 23, 2014

September 23, 2014

Total # Posts: 25,175

**Fractions**

(5 1/2) / (3/4) = 11/2 * 4/3 = 22/3 = 7 1/3 So, she has enough for 7 servings, with 1/3 serving left over. For 10 people, she needs to have only 11/2 * 1/10 = 11/20 cup per serving 10 servings of 3/4 cup each is 30/4 = 7 1/2 cups
*September 23, 2014*

**math**

If the numbers are relatively prime, then x(x-7) = 60 x^2 - 7x - 60 = 0 (x-12)(x+5) = 0 So, the numbers are 12 and 5
*September 23, 2014*

**Math**

To use the quadratic formula, you need to arrange things so that you have y = ax^2 + bx + c So, (x - 10 )(x + 9 ) = 2 x^2-x-90 = 2 x^2 - x - 92 = 0 Now just apply the formula.
*September 23, 2014*

**math**

(-a,b)
*September 23, 2014*

**Math**

x^2 + 4 x = 4 x^2 + 4x - 4 = 0 Now just apply the formula.
*September 23, 2014*

**Maths**

The cylinder has radius r The cone has radius 2r So, the ratio of volumes is (πr^2h)/(π(2r)^2h/3) = (πr^2h)/(4πr^2h/3) = 3/4
*September 23, 2014*

**College Pre-Calculus**

m(f) = f/5280
*September 23, 2014*

**Math**

27/3 + 5*2 = 19
*September 22, 2014*

**math**

1kg/(4.8g/cm^3) = 208.333 cm^3 So, now you know that 4π/3 r^3 = 208.333
*September 22, 2014*

**Algebra1**

either or both
*September 22, 2014*

**physics**

F = ma -1.50*10^4 = (1.96*10^4/9.81)(a)
*September 22, 2014*

**math**

same as what?
*September 22, 2014*

**Math**

77 = 11*7, so (6+5)*(9-2)
*September 22, 2014*

**algebra**

Just work it step by step: 105/(-20+15) ------------------- 45/(-9)+12 105/(-5) ------------ -5+12 -21 --------- 7 -3
*September 22, 2014*

**Math**

r(x) = (600-4x)(250+4x) Now plug and chug.
*September 22, 2014*

**Algebra**

If x lbs at $7, then 7x + 5(50-x) = 5.79(50)
*September 22, 2014*

**math**

what difference does it make how far the sun is from earth? Unless the distance to Mars is measured in a.u.
*September 22, 2014*

**Advance Algebra**

v(x) = x(12-2x)(10-2x) Since the sides must have positive length, we need 10-2x > 0, or x<5 Since the cuts must also have nonzero length, x>0, so the domain is 0 < x < 5
*September 22, 2014*

**math**

After t minutes, the positions are (if P=(0,0)) turtle: (0,4t) snail: (50,-2t) So, the distance d can be found from d^2 = 50^2 + (6t)^2
*September 22, 2014*

**Algebra 2**

just expand as you normally would a polynomial, and you get 30i^3 + 125i^2 + 120i But, once you recall that i^2 = -1 i^3 = -i, you have -125 + 90i
*September 22, 2014*

**Geometry**

Hard to parse the garbled sentence, but if the hill slopes at a 30 degree angle, then the tree makes angles of 60 and 120 with the hill. To explain, just draw a diagram and label all the angles.
*September 22, 2014*

**algebra 2**

First, that's equal to, NOT too! It's a lot easier just to write x >= 2. With that said, let's proceed. #1: ok #2: ok #3: Hmmm. This one is no harder than the first two, just a bit longer. 4(1-3n)-14>4(2n+3)-9n 4-12n-14 > 8n+12-9n -12n-10 > -n+12 -11n &...
*September 22, 2014*

**trigonometry**

A wheel with a 15-inch diameter is turning at the rate of 60 revolutions per minute. To the nearest inch per minute, what is the linear speed of a point on the rim?
*September 22, 2014*

**Maths**

start factoring: 2*2198 4*1099 4*7*157 = 28*157 What's with "using the numbers 1-9"? Seems like a stupid condition.
*September 22, 2014*

**Math**

(b) no angles provided
*September 22, 2014*

**algebra**

clearly, when 50.00 + 3.50x = 75.00 + 2.25x Now just solve for x.
*September 22, 2014*

**algebra**

5n+10d+25q = 325 n = d+2 q = n+1 Now just start substituting in to solve for the variables.
*September 22, 2014*

**Math**

What's the trouble? Just start writing the words as equations. We are told: a+b+c = 18 a = 2(c-b) (because c > b) b = (a+c)/2 Now just go through the usual procedures to solve several equations.
*September 22, 2014*

**Math**

correction on #1. What I gave was the solution for a particular radius. Since we have to consider all possible such circles, the locus is the perpendicular bisector of the line joining centers of the circles. All points on that line are equidistant from the two centers.
*September 22, 2014*

**Math**

since |z-c|=r is a circle of radius r, |z+1| = |z+i| is the intersection of two circles. If z = x+yi, Re z = x |z-1|^2 = (x-1)^2 + y^2 So, you need x^2 = (x-1)^2
*September 22, 2014*

**math**

If there are x,y,z of each cost, we have x+y+z = 20 4.00x + 0.25y + 0.50z = 20.00 Since we have only two equations, there are multiple solutions. Let's work with knowing x. Then we have y = 14x-40 z = 60-15x Since y and z must be positive, we need x >= 3 and x < 4. ...
*September 22, 2014*

**math**

(150*15)/500 = 4.5 so, now you can figure it out, right?
*September 22, 2014*

**Math Help Please**

just solve 16t^2 = 1614
*September 22, 2014*

**Math**

how are the 6 fields to be arranged? 2x3: 9x+8y = 1200 a = 6xy = 6x(1200-9x)/8 max area at x = 200/3 1x6: 12x+7y = 1200 a = 6xy = 6x(1200-12x)/7 max area at x = 50 Note that the fencing is divided equally among lengths and widths.
*September 22, 2014*

**math**

Ben takes time t = (d/2)/r + (d/2)/w = d/(2(r+w)) Bob covers distance w(t/2) + r(t/2) = d so Bob's time is 2d/(r+w) So, which time is less?
*September 22, 2014*

**Algebra**

9-c < 2 c > 7 -3c > 15 c < -5 so, c < -5 or c > 7 See http://www.wolframalpha.com/input/?i=solve+9+-+c+%3C2+or+-3c+%3E+15+
*September 22, 2014*

**Precal**

sec θ = r/x = √218/-7
*September 22, 2014*

**Math**

3^2-12/(6-3)*8 9-12/3*8 9-4*8 9-32 -23
*September 21, 2014*

**Math - Madison the Mooch**

The equation describes an ellipse. There is no inverse, because each value of x corresponds to 2 values of y (the vertical line test). There is no such thing as an inverse equation. If you want to find x as a function of y, then 2x^2 = 4 - 3y^2 x^2 = (4-3y^2)/2 Now, there is a...
*September 21, 2014*

**Math**

False even without doing the math, the left side is odd and the right side is even.
*September 21, 2014*

**AP Calc. AB**

correct.
*September 21, 2014*

**algebra**

(2,10,5)
*September 21, 2014*

**Math**

(6-6)/(6x6+6)=0
*September 21, 2014*

**Algebra**

as usual, first just clear fractions: (n+9)(7) = 6(d+9) (n-7)(3) = 2(d-7) 7n+63 = 6d+54 3n-21 = 2d-14 7n-6d = -9 3n-2d = 7 Now can you solve for n and d?
*September 21, 2014*

**Algebra**

Just put the words into symbols. If the original fraction is n/d, then (n+9)/(d+9) = 6/7 (n-7)/(d-7) = 2/3 Now just solve for n and d.
*September 21, 2014*

**math**

If the base of the rectangle has length 2x, and height y, the area is a = 2xy = 2x√(1-x^2/16)(4) = 2x√(16-x^2) da/dx = 4(8-x^2)/√(16-x^2) so, max area occurs at x=√8, and the rectangle is 2√8 by √2
*September 21, 2014*

**AP Calc. AB**

Clearly A is not continuous at x = -1, since the denominator is zero. The domain of √u is u >= 0. So, we need x+6 >= 0 The domain of sin x is all reals, so it doesn't affect the result. we know that lim sin(x)/x = 1, so sin(2x)/(2x) is 1. So, lim sin(2x)/x = 2...
*September 21, 2014*

**Algebra**

The only question I see is whether x^3-2x^2-1+2 = 0 For some values of x, it is. I suspect a typo, since you have no x term, and two constant terms. Why not fix the typo and then ask your real question?
*September 21, 2014*

**Math.**

x - 8.77 = 23.40
*September 21, 2014*

**math**

2.3x = 48.00
*September 21, 2014*

**Math**

20*27 = ?
*September 21, 2014*

**Math**

100/200 = x/53.40
*September 21, 2014*

**Math**

what is the difference between 10 and 6? It is 10-6, or 4. So, the difference here is just x = 39.50 - 23.50
*September 21, 2014*

**math**

clearly (0,5) is is a set of x values, since x is in that interval. I'm sure it is just to restrict us to a single period of 2π. 1+x <= f(x) <= 3+sin πx as x->2, 1+2 <= f(x) <= 3
*September 21, 2014*

**math**

#1: c = 9.95 + .10m #2: c = 12.95 + .08m
*September 21, 2014*

**maths**

In triangles adb and adc, angle adb = angle adc bd = dc ad = ad So, the triangles are congruent, meaning ab = ac so abc is isosceles.
*September 21, 2014*

**Algebra**

correct
*September 21, 2014*

**math**

If the digits are a and b then 10a+b = 8(a+b) 10a+b - 45 = 10b + a The number is 72
*September 21, 2014*

**Algebra 2 (Please, help me!)**

well, it just means that all points have become 1/3 as far away from the origin as they were. Just divide all the coordinates by 3: (9,-6) -> (3,-2) and so on
*September 21, 2014*

**math**

the area grows as the square of the length ratio. So, the sides are in the ratio √9:√4 = 3:2. So also are the perimeters.
*September 21, 2014*

**trigonometry**

as usual, draw a diagram, and review your basic trig function definitions: tan θ = 5100/12000 So, θ = arctan(51/120)
*September 21, 2014*

**Physics help ASAP**

Suppose you are visiting a planet in a distant part of the galaxy.To determine the acceleration due to gravity on this planet, you drop a rock from a height of 55 m. The rock strikes the ground 1.9 s later.How many times greater is the acceleration due to gravity on this ...
*September 20, 2014*

**Physics**

A baseball is thrown upward with an initial speed of 35 m/s. What is the speed at t = 2 s?
*September 20, 2014*

**physicas**

A baseball is thrown upward with an initial speed of 35 m/s. What is the speed at t = 2 s?
*September 20, 2014*

**Physics**

A basketball is shot from an initial height of 2.4 m with an initial speed (v0 = 12 m/s) directed at an angle (35 degrees) above the horizontal. Additional information: Height of the basket is 3.05 m Find how far away the player is standing.
*September 20, 2014*

**math**

generally true, but the right angle is not at exactly 1:15, because the hour hand has also moved 1/4 of the way from 1 to 2. after m minutes, the minute hand has moved m/60*360 = 6m° the hour hand has moved to 30+m/2° So, we need to find m when 6m = 30 + m/2 + 90 11m/2...
*September 20, 2014*

**Operating system**

so, you expect us to do your research? I'd start with google, and then start reading.
*September 20, 2014*

**Algebr**

correct
*September 20, 2014*

**math**

the difference between two number m and n is m-n. So, you are comparing -14 and -10. The difference is -4 - (-10) = -4 + 10 = 6 That is, he lost 6 more ounces this year than last year.
*September 20, 2014*

**Pre-Cal**

but, at (1,-1), x^2+y^2 = 2 The maximum occurs when x = 2/√29 y = -5/√29
*September 20, 2014*

**math**

5h^(2/5) = 3645/5 h^(2/5) = 3645/25 h^(2/5) = 3^6/5 h^(1/5) = 27/√5 h = (27/√5)^5 That's an unusual result. I suspect a typo. If so, fix it and follow the same logic to arrive at the correct answer.
*September 20, 2014*

**Algebra**

you are correct.
*September 20, 2014*

**Math**

(b) recall that the vertex of a parabola is at t = -b/2a. In this case, that's 32/32 = 1. (a) just plug in t=1.
*September 20, 2014*

**Algebra 2--Please, help me!**

#1 ok #2 ok #3 right value, but not scientific notation #4 ok #5 Well, if it is a function, then no last name maps to more than one age. What do you think? #6 r(d) 75.00-3.50d I think you can answer the other parts of this one, no?
*September 20, 2014*

**factorise completely**

a(2x-3y) + (2x-3y) (a+1)(2x-3y)
*September 20, 2014*

**math**

Just start at -8 and start listing the odd numbers: -7 -5 -3 -1 1 3 5
*September 20, 2014*

**Math**

5/8 + 1/2 = 9/8 Only 7/8 were sick, so 2/8 had both
*September 20, 2014*

**Math**

13000/(1 - 2/5 - 1/6) = ?
*September 20, 2014*

**Math (Equation of a circle)**

clearly the radius is 2, since the center is at y=2. So, the equation is (x-3)^2 + (y-2)^2 = 4
*September 20, 2014*

**Math**

a^74/a^33 = 26p/-2p = -13 so, a = (-13)^(1/41)
*September 20, 2014*

**math**

x <= -2 has the filled dot at -2, but the shading continues all the way to the left. No idea what all those other values are supposed to be.
*September 19, 2014*

**Business math**

You need to find x where 12400(.042) = x(.0385)
*September 19, 2014*

**math**

to find how many times greater 6 is than 3, divide 6 by 3. So, for your birds, divide (13 9/10) by (3 1/2). Your answer 278/70 is the correct value, but it could be simplified to 139/35. Since 3.9714 is only approximate, it is hard to recover the fraction. Both your answers ...
*September 19, 2014*

**Math Help**

just replace all the x's with (x-1): f(x-1) = 4(x-1)^2 + 3(x-1) - 3 I assume you can simplify that.
*September 19, 2014*

**Algebra 2**

r(d) = 75.00 - 3.50d
*September 19, 2014*

**Algebra 2**

#3 is the correct value, but it is not scientific notation. The others are ok.
*September 19, 2014*

**Math**

Do a little simplification first. As long as x≠5, (x^2-25)/(x-5) = (x-5)(x+5)/(x-5) = x+5 So, what you have is, f(x) = x+5 if x <= -1 2x-3 if x > -1 So, since 4 > -1, f(4) = 8-3 = 5 And, since -1 <= -1, f(-1) = -1+5 = 4
*September 19, 2014*

**math skill sheet 777**

add up the values of 1 of each coin: 1+5+10+25 = 41 Now, how many 41's in 205? That's how many of each coin you have. so, now you can total up how many coins you have in total.
*September 19, 2014*

**Math help**

By "sum" I assume you mean the sum of three numbers in any row, with the center in each row. One way is surely to place the middle number (29) in the center. Then in pairs place the other numbers on ends of diameters, increasing on one end, decreasing on the other, ...
*September 19, 2014*

**Math**

No, D has the solution y=0 6y-2 = 2y-2 4y = 0 y=0 C is the one you want: 7x+5 = 7x+5 Both sides represent the same value, so any solution of the left side is also a solution on the right side.
*September 19, 2014*

**Pre-Calculus Questions**

(1) The slope is -6/6 = -1 So, in point-slope, we have y-3 = -1(x+5) Now massage that into slope-intercept form. Clearly, when x=0, y = -3 Since y = (x-3)(x+1), y=0 when x is -1 or 3. So, draw a parabola with those roots, which opens upward. Recall that the vertex occurs ...
*September 19, 2014*

**physics**

x(t) = Xo + Vot - 1/2 at^2 So, (5Vo - 25/2 a)-(4Vo - 16/2 a) = 100 (8Vo - 64/2 a)-(7Vo - 49/2 a) = 120 so, Vo = 70 a = -20/3 Now just figure x(20)-x(19)
*September 19, 2014*

**Math**

Just consider each ball's chances as it is drawn: 3/15 * 2/14 * 1/13 * 12/12 * 11/11 * ... = 1/455 Note that after all the red balls are drawn, there is a 100% chance that the rest will be white. Also, the order does not matter. If the order were WWRWWRWR the chances would...
*September 19, 2014*

**Algebra 2 Answer Check**

#3: Typo? I get 13xy #5: -2x^4y^7 / x^5 = -2y^7/x Now cube that. And watch that - sign
*September 19, 2014*

**Math**

Clearly a = 250000 r = 1/5 Now just use your sum formula.
*September 19, 2014*

**MATHS**

since sec^2 θ - tan^2 θ = 1, you have -8(sec^2 θ - tan^2 θ) = -8 Better review your basic identities. The most important is, of course, sin^2 θ + cos^2 θ = 1 divide through by cos^2 and you have tan^2 θ + 1 = sec^2 θ
*September 19, 2014*

**Math**

Surely you can determine T1 ?? Clearly d = -2b So now just apply your formulas.
*September 19, 2014*

**Algebra 2**

well, f(-x) = -x/(-x-1) = x/(x+1) ≠ -f(x) so no symmetry about (0,0) Also, f(-x) ≠ f(x), so no symmetry about the y-axis f^-1(x) = x/(x-1), so there is symmetry about the line y=x. See http://www.wolframalpha.com/input/?i=inverse+x%2F%28x-1%29
*September 19, 2014*

**Algebra**

Better review your symmetry section. No ideas on any of them?
*September 19, 2014*

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