Saturday

February 28, 2015

February 28, 2015

Total # Posts: 29,284

**Algebra 1**

A local citizen wants to fence a rectangular community garden. The length of the garden should be at least 110 ft and the distance around should be no more than 380 ft. What system of inequalities would represent the possible dimensions of the garden?
*December 24, 2014*

**Good One, Damon**

Oh, yeah. I like it. I think I pooh-poohed that derivation on another problem, thinking you had short-circuited the product rule, but this time I studied it more closely. Of course dv is just a thin circle on top of the cone (pi r^2) times the thickness (dh)!
*December 24, 2014*

**Calculus**

Or, you can use the product rule: v = 1/3 pi r^2 h dv/dt = 1/3 pi (2rh dr/dt + r^2 dh/dt) Then you have to fill in the other quantities to get dh/dt. Note that since r = h/2, dr/dt = 1/2 dh/dt
*December 24, 2014*

**Calculus**

Once you master the math, you can work on the spelling!... we know h = 2r, so r = h/2 v = 1/3 pi r^2 h = 1/12 pi h^3 dv/dt = 1/4 pi h^2 dh/dt So, now just plug in the numbers you have for h and dv/dt to find dh/dt.
*December 24, 2014*

**Math**

which bank is that? I'll put my money there!
*December 24, 2014*

**math**

A:B:C = 3:7:8 A:B+10:C-10 = 3:8:7 That means that b/c = 7/8 (b+10)/(c-10) = 8/7 Solving that, we have b=70 c=80 Now, you can figure a.
*December 24, 2014*

**Algebra 1**

How many solutions does then system of equation have? y-5x = -6 and 3y-15x=-12
*December 23, 2014*

**Algebra 1**

How many solutions does the system of equation have? x-4y =12 and 5x-20y =60
*December 23, 2014*

**Math I Have no idea PlEASE help me**

well, you know that flying east-to-west, the plane goes 270 mi/hr going to the east, it flies at 330 mi/hr. So, just make your table for each 200-mile interval. That's 15 entries in each direction.
*December 23, 2014*

**Algebra 1**

How many solutions does the system of equations have? y=4x +3 and 2y-8x=3
*December 23, 2014*

**Algebra 1**

How many solutions does the system of equations have? x=-4y+4 and 2x+8y=8
*December 23, 2014*

**Geometry**

It might help if you list the vertices of the quadrilateral, say, in clockwise order or something. What you have said gives no real good picture of the figure.
*December 23, 2014*

**math**

Ah, yes. You are correct. I had misread the problem. Good work.
*December 23, 2014*

**math**

Clearly, the fixed charge is always 700. You must want the variable charge per unit. That means you want to solve 700+200x = 5/4(700+100x) unless something else has been garbled.
*December 23, 2014*

**Maths**

6912/(3+4) = 987.4 So, length = 3*987.4 breadth = 4*987.4
*December 23, 2014*

**Algebra**

just write down what you know. If there are x at 5 points and y at 3 points, then x+y = 38 5x+2y = 100
*December 22, 2014*

**Grammer**

since "none" is singular, none of the choices is correct.
*December 22, 2014*

**science **

A running back has 3500 J of kinetic energy and is running at a speed of 8 m/s. Calculate his mass.
*December 21, 2014*

**Integration**

The trapezoidal cross-section for water at depth 1/2 + h/2 = (1+h)/2 So, the surface area of the water at depth h is 10*(1+h)/2 = 5(1+h) So, the volume of the sheet of water is 5(1+h) dh That means that the weight of the water (at 1000kg/m^3) layer is 5(1+h) dh * 1000 * 9.8 ...
*December 21, 2014*

**ap calc**

Is f(x) continuous at x=1? 2x-x^2 = 1 2x^2-4x+3 = 1 So, yes. The derivative exists everywhere in (0,2). So, f(x) satisfies the MVT f(2) = 3 f(0) = 0 So, the slope of the secant is is 3/2 Where does f'(c) = 3/2? 2-2x = 3/2 x = 1/4 y = 3/2 (x-1/4) + 7/16 4x-4 = 3/2 x = 11/8 ...
*December 21, 2014*

**Algebra**

Just plug the numbers into your amortization formula.
*December 21, 2014*

**College Math**

find the mean and the standard deviation. The Z score of 3.1 is how many std it is away from the mean.
*December 21, 2014*

**College Math**

zero The Z score of the mean is always zero, because it is zero std away from the mean. If you really have no clue, it's probably time to review just what a Z score is.
*December 21, 2014*

**College Math**

30(1.6)^n = 30000 1.6^n = 1000 n log 1.6 = log 1000 n = log1000/log1.6 = 14.7
*December 21, 2014*

**Algebra 1**

just plug in the numvers and check. 4 > 4*3-5 ? 4 > 12-5 ? 4 > 7 ? NO So, try the others.
*December 21, 2014*

**Algebra 1**

Which ordered pair is a solution of the inequality? y>= 4x-5 3,4 2,1 3,0 1,1
*December 21, 2014*

**math**

what a deal. I suspect you want to start with what you know: 4s+3j = 181 1s+2j = 94
*December 21, 2014*

**ap calc**

y = x ln x + (1-x) ln(1-x) y' = lnx + 1 - (1-x)/(1-x) - ln(1-x) = lnx - ln(1-x) = ln(x/(1-x)) y'=0 when x/(1-x) = 1 x = 1-x x = 1/2
*December 21, 2014*

**Math-How do I do this problem?**

Hmmm. I get r = 7/24 h so, dr = 7/24 dh r = 35/12 when h=10 v = 1/3 pi r^2 h using the product rule, dv = 1/3 pi (2rh dr + r^2 dh) 12 = pi/3 (2*(35/12)(10)(7/24 dh)+(35/12)^2 dh) 12 = 1225/144 pi dh dh = 1728/1225 pi = 12^3/35^2 pi Maybe you can figure out whether one of us is...
*December 21, 2014*

**Calculus**

The curves intersect at (-4,-12) and (3,-5) So, the area is just the sum of all the tiny rectangles with width dx, and height the distance between the curves: A = ∫[-4,3] (4-x^2)-(x-8) dx = ∫[-4,3] -x^2-x+12 dx = -1/3 x^3 - 1/2 x^2 + 12x [-4,3] = 343/6
*December 21, 2014*

**Calculus**

Try checking here: https://in.answers.yahoo.com/question/index?qid=20101212020426AAEM8Zp and https://answers.yahoo.com/question/index?qid=20131119231723AABFnM7
*December 21, 2014*

**Algebra 1**

What about from the following answers 0,1 -1,0 1,0 0,0 I'm a 68 year old grandfather trying to help his grandson.
*December 20, 2014*

**Algebra 1**

the solution set for y<x is half of the plane. There are infinitely many points on each axis which satisfy the inequality.
*December 20, 2014*

**Algebra 1**

Which point on the axis satisfies the inequality y<x?
*December 20, 2014*

**Algebra 1**

What about from the followuing answers 4 -2 2 -4
*December 20, 2014*

**Algebra 1**

the point on the x-axis is where y=0, SO x - 2y <= 4 now plug in y=0 and you can see what x is. I think you need a bit more information here.
*December 20, 2014*

**Algebra 1**

In the graph of the inequality X - 2y is less then or equal,to 4, which is a value for x on the inequality line and the x axis?
*December 20, 2014*

**Algebra 1**

I'm 68 years old and don't remember some of these things and am trying to help grandson.
*December 20, 2014*

**Algebra 1**

draw the axes. Label each quadrant ++ +- -+ or -- and then let us know, ok?
*December 20, 2014*

**Algebra 1**

If x is greater then or equal and y is greater then or equal to 0 then which quadrant holds the solution?
*December 20, 2014*

**Algebra 1**

the rate of change is the slope of the line. That is, if x changes by 1, how much does y change? In the slope-intercept form, the rate of change (slope) is m, in y = mx+b The point-slope form of a line is y-k = m(x-h) where the line passes through (h,k) with slope m. It's ...
*December 20, 2014*

**physics**

well, you know the equation of motion is h(t) = vt - 4.9t^2 So, h is max at t = v/9.8 So, plug in t=v/9.8 into vt - 4.9t^2 = 1.5 and solve for v.
*December 20, 2014*

**physics please help**

If thrown down with initial velocity v, then just solve 109 - vt - 4.9t^2 = 0 plug in t=2.40 and find v.
*December 20, 2014*

**Physics please help**

the equation of the height is h(t) = 29t - 4.9t^2 Now just find the vertex of the parabola for the max height. Of course, the ball comes down exactly as fast as it went up -- got to conserve that momentum, eh?
*December 20, 2014*

**ap calc**

f(0) = 0 f(√π) = 0 So, we need c in (0,π) such that f'(c) = 0 f'(x) = 2x cos(x^2) 2x cos(x^2) = 0 Clearly c=√(π/2) satisfies the theorem.
*December 19, 2014*

**Math**

just divide each y by its x. Is the ratio constant? If so, that means y/x = k,or y=kx, a direct variation.
*December 19, 2014*

**math**

We have a winner!
*December 19, 2014*

**Math**

Note that y increases 5 when x increases 1. So, the rule will look like y = 5x But, when x=0, 5x=0 and we want y = -3. So, y = 5x-3
*December 19, 2014*

**Intermedia Algebra**

well, you have the formula. Use it. What do you get?
*December 19, 2014*

**Algebra**

Neil: 2 mi/hr current: 1 mi/hr Check: In 1 hour, Neil rowed 1 mi upstream. In 1 more hour, he rowed 3 mi downstream back to camp In those 2 hours, the log floated 2 miles downstream to camp
*December 19, 2014*

**math**

Hmph. Musta missed that. Using 22/7 for pi is just not rational!
*December 19, 2014*

**math**

so, what does 22/7/2 mean?
*December 19, 2014*

**math**

A makes 3x B makes 4x A spends 4y B spends 5y So, A saves 3x-4y B saves 4x-5y So, can you solve (3x-4y)/(4x-5y) = 9/10 ? 10(3x-4y) = 9(4x-5y) 30x-40y = 36x-45y 6x = 5y Can't happen try the other fractions.
*December 19, 2014*

**Math**

dy = 1/3 x^-2/3 dx At x=4, dy = 1/48 dx So, use dx=0.2 to find dy, and add that to y(64)=4 Note also that since the slope is 1/48, y-4 = 1/48 (x-64)
*December 19, 2014*

**Math**

this is just algebra I, after finding the slope of the tangent line... since y = x^(1/3) y' = 1/3 x^-(2/3) y(27) = 3 y'(27) = 1/9 So, now you have a point and a slope, so the line is y-3 = 1/9 (x-27) I'll let you massage the equation. Now you can use that line to ...
*December 19, 2014*

**Math**

since v = 4/3 pi r^3 and c = 2pi r, r = c/2pi, and v = 4/3 pi (c/2pi)^3 v = 1/(6pi^2) c^3 so, dv = 1/(2pi^2) c^2 dc so, now you have dc and can evaluate dv
*December 19, 2014*

**math**

Post a problem, showing your work as far as you got. Hope someone who knows something drops by to help out.
*December 19, 2014*

**precalculus**

[-7,-4)U(-4,-1)
*December 19, 2014*

**precalculus**

revenue r(x) = (1000+4x)(500-8x) Just find the vertex of that parabola to get the x desired, then figure the other items based on that.
*December 19, 2014*

**Algebra**

ever hear of the slope-intercept form of the line? Just plug in the numbers given.
*December 19, 2014*

**math**

A makes 4x B makes 3x A saves 3x/4 So, A spends 4x - 3x/4 = 13x/4 B spends (4/5)(13x/4) = 13x/5 So, B saves 3x - 13x/5 = 2x/5 The savings ratio is thus (3x/4):(2x/5) = 15:8
*December 19, 2014*

**algebra**

I think you need to (a) indicate how far apart are the integers (b) just what it is you want to know.
*December 18, 2014*

**math**

Hard to say: out = in-16 ? out = in/3 ? out = 2 * in(mod 5) ? One data point does not give much to go on.
*December 18, 2014*

**Algebra 1**

depends on the equations. Mainly, as with most things, skill comes with practice. Just doing the 5 assigned homework problems isn't going to give you the practice you need. I'm good at it because I have done hundreds of them.
*December 18, 2014*

**Algebra 1**

When solving a system of equations, how do you determine which method to use?
*December 18, 2014*

**Algebra math**

have you considered taking a typing class? You want to find when the height h: 80t - 16t^2 = 0 16t(5-t) = 0 I think it's clear now when h=0. (Just in case you haven't figured it out, the ball hits the ground when the height is zero...)
*December 18, 2014*

**Algebra 1**

thank you
*December 18, 2014*

**Algebra 1**

Which method would be the simplest way to solve the system? 7x +5y = 19 -7x-2y = -16 graphing substitution elimination or distributive
*December 18, 2014*

**Algebra 1**

I forgot my answer which is quadrant III.
*December 18, 2014*

**Algebra 1**

In which quadrant does the solution ofthen system fall? y=x-1 y= -3x-5
*December 18, 2014*

**Algebra 1**

$7.00 Thank you
*December 18, 2014*

**Algebra 1**

The cost of 4 scarves and 6 hats is $52.00. The cost of 2 hats is $1.00 more than the cost of 1 scarf. What is the cost of 1 scarf?
*December 18, 2014*

**Algebra 1**

Thank you
*December 18, 2014*

**Algebra 1**

zero solutions. -3x+6y cannot equal both 10 and -4. The lines are parallel, and so, do not intersect.
*December 18, 2014*

**Algebra 1**

The first line should read -3x
*December 18, 2014*

**Algebra 1**

How many solutions does this system have? *3x + 6y = 10 -3x + 6y = -4
*December 18, 2014*

**algebra 1**

that is correct. If you dislike working with fractions, you can start over and eliminate y instead of x.
*December 18, 2014*

**algebra 1**

-16x-2y=-18 8x+y=9 Multiply the 2nd by 2 to get -16x-2y=-18 16x+2y = 18 These are the same line. There are infinitely many solutions. Any point on one line is also on the other, as the lines coincide.
*December 18, 2014*

**physics**

when you say constant velocity, that means zero acceleration.
*December 18, 2014*

**Chemistry**

(.0658*0.3)/(.015)
*December 18, 2014*

**Math**

count the deposits, and count the amounts: If there were x deposits at $5, and y at $3.50, then we know x+y=14 5x+3.50y=59.50 Now just plug and chug.
*December 18, 2014*

**Chemistry**

Since PV is constant, and you have increased the volume by a factor of 1000, the pressure is reduced by a factor of 1000.
*December 18, 2014*

**math**

Since the 54% and the 63% grades count as 80% of her grade (and assuming therefore that each counts as 40%), the final grade is (54+63)(0.4) + 80(.2) = 62.8
*December 18, 2014*

**math**

If they sell x tacos, the profit for the day is 3.25x - 210 So, set that > 0 and solve for x.
*December 18, 2014*

**Math**

correckit!
*December 18, 2014*

**Math**

if it is not included, then you subtract it from the total. So, ...
*December 18, 2014*

**math algebra**

Since y is the cost of a sandwich with x extra veggies, the y-intercept is the cost with 0 veggies. the two extra veggies (5-3) cost $1.00 more. So, the veggies are $0.50 each. That means 0 extra veggies (the y-intercept) must be at 5.25-1.50 = 3.75 Looks like (D) to me y = 0....
*December 18, 2014*

**physic**

well, torque = radius * force T = rF if the radius is doubled, the new torque is T' = (2r)F = 2rF = 2T
*December 18, 2014*

**Physics**

If he cleared the bar at the top of his swing, then all his speed was horizontal, at 10.2 m/s. All that stuff about mass and height is just noise. Trying to incorporate other forces is impossible without further data.
*December 18, 2014*

**Physics**

speed s is found by conserving momentum: 800s = 3*10 time = 6.4/s
*December 18, 2014*

**math**

d/dr (r^3) = 3r^2 It's just the normal power formula So, dV/dr = (4/3)pi (3r^2) dV = 4pi r^2 dr Don't lose track of the dr when doing related rates
*December 18, 2014*

**Math**

well, dy = -1 / 2√(7-x) dx So, just plug in your numbers
*December 18, 2014*

**algebra**

you need an equation for the number of plays and the points for them: x+y = 21 3x+y = 49
*December 18, 2014*

**math**

The price p for e eggs is p/e = 1/6
*December 18, 2014*

**Math**

well, just compare the two plans for how much it costs the patient: 400 + 0.35(x-400) > 1000 + 0.25(x-1000)
*December 18, 2014*

**math**

.85p = 76
*December 18, 2014*

**Math- algebra**

well, you want y when x = -b/2a = 26/32 google will evaluate many algebraic expressions. Just type it into the search box.
*December 17, 2014*

**math**

15/x = cos 60°
*December 17, 2014*

**math**

clearly, 23.25/3 or 7.75
*December 17, 2014*

**math**

well write the ratios and see which are the same when reduced to lowest terms. For example 6/3 and 20/10 are the same ratio
*December 17, 2014*

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