Sunday

May 29, 2016
Total # Posts: 40,876

**Math Help!!!**

looks good to me.
*April 8, 2016*

**geometry**

I'd start with this: The circle's equation is (x - a/2)^2 + (y - b/2)^2 = (a^2+b^2)/4 If a chord intersects the x-axis at x=c, then the slope of the chord is (b)/(a-c) so, the equation of the chord is y = b/(a-c) (x-c) and the length of the chord is 2sqrt((a-c)^2 + b^2...
*April 8, 2016*

**Algebra**

√363 - 3√27 = √(121*3) - 3√(9*3) = 11√3 - 3*3√3 = 2√3
*April 8, 2016*

**Algebra 1**

n = n^1 so, adding exponents, n^-4•n = n^-4 • n^1 = n^(-4+1) = n^-3 or, since n^-4 = 1/n^4, 1/n^4 • n = n/n^4 = 1/n^3
*April 8, 2016*

**mathematics**

all sides are 10, so its base is 10. 10h = 84 h = 84/10 = 42/5
*April 8, 2016*

**Math**

well, what is 100% of 25? Naturally, that's 25, since 100% is all of something. 500% is 5 times 100%, so that is just 5*25 = 125 a little thought can help a lot while you're waiting, rather than whining about it.
*April 7, 2016*

**Mathematics**

yes. the angle is 1/5 of 360°, or 72° and that's rotational symmetry, not system.
*April 7, 2016*

**math**

4.1x10^5 = 4.1 x 100,000 = 410,000
*April 7, 2016*

**Math**

10*9*8 = 720
*April 7, 2016*

**Algebra**

-7 < y <= 3
*April 7, 2016*

**Math**

1/5 + 1/4 = 9/20 so, the rest is 11/20 11/20 x = 11 so, 1/20 x = 1 x = 20 1/5 of 20 is 4 to her brother
*April 7, 2016*

**calc 2**

for our function, y' = 6k(kx)^5 so, we want other curves whose slope is y' = -1/(6k^6) x^-5 y = 1/(24k^6 x^4) or, to make things look more similar, y = 1/(24k^2) (kx)^-4
*April 7, 2016*

**Newtons Second Law**

Net force is 7500-2200-5000 = 300N F = ma, so a = 300N/1200kg = 0.25 m/s^2 the actual speed of the car does not matter.
*April 7, 2016*

**Algebra**

The fill rate is clearly 825 ft^3/hr At 10 hours, that will be 8250 ft^3. no idea of the percent filled. How big is the silo?
*April 7, 2016*

**pre ap math**

cool!
*April 7, 2016*

**Math**

factor out the 9: 9(y^2-9) difference of squares: 9(y-3)(y+3)
*April 7, 2016*

**Algebra**

If there were x oz of almonds, then the rest (300-x) was tea. 0.95x + 2.15(300-x) = 1.85(300)
*April 7, 2016*

**Math**

3 yds = 108 in. So, length+width = 54 in. Starting with w=6, we thus have dimensions of 6,48 7,47 ... 12,42
*April 7, 2016*

**Algebra**

looks good to me.
*April 7, 2016*

**Algebra**

1/5 + 1/12 = 1/x
*April 7, 2016*

**chemistry**

66s is 6 half-lives, so 49.0 * (1/2)^6 = 0.765 μg
*April 7, 2016*

**Chemistry**

80(1/2)^t = 10 (1/2)^t = 1/8 t = 3 so, 45 days is 3 half-lives
*April 7, 2016*

**Algebra**

since time = distance/speed, 132/(x+11) = 132/x - 2 x = 22 6 hrs at 22 mph 4 hrs at 33 mph
*April 7, 2016*

**Algebra**

If it takes A x days, it takes B 2x days. 1/x + 1/(2x) = 1/5 3/(2x) = 1/5 x = 15/2 So, it takes B 15/2 days, and A 15/4 days
*April 7, 2016*

**Algebra II**

so, 8=4p p=2 that is the distance from the vertex to the focus. All you need to do is (a) read what we gave you (b) think about it a bit
*April 7, 2016*

**Algebra II**

for the parabola y^2 = 4px the vertex is at a distance p from the focus.
*April 7, 2016*

**Math**

which are the right angles?
*April 7, 2016*

**chemistry**

142km * 1gal/27mi * .6214mi/km * 3,78L/gal = 12.35L
*April 7, 2016*

**Algebra**

If x at 2 pts, then 24-x at 3 pts. So, adding up all the points, 2x + 3(24-x) = 53 x = 19 for 2-pts so, 24-x = 5 for 3-pts
*April 7, 2016*

**math**

In QI, x>0 and y>0 so, where are x<0 and y<0 ?
*April 7, 2016*

**Chemistry**

What is the mole fraction of NaBr in an aqueous solution that contains 20.1% NaBr (weight/weight%)?
*April 7, 2016*

**Geometry**

For a pentagon with radius r, the apothem is a = r cos 36° = 0.8090r So, the radius of B is .8090 the radius of A. So, B's area is .8090^2 the area of A. So, A's area is 1.53 times the area of B.
*April 7, 2016*

**Algebra**

on the left, you have 4x+2 so on the right, if you have 4x + ? where ? is anything but 2, there can be no solution.
*April 7, 2016*

**Algebra**

translations and reflections do not change distances. So, F'G' is the same length as FG.
*April 7, 2016*

**Algebra**

well, since the grade does not always increase or decrease, it cannot be linear. So, A and B are out. Now look at the data and pick C or D.
*April 7, 2016*

**Math**

clearly the last digit must be 0 or 5 The 1st digit cannot be zero. So, there are 1st digit 5: 1*4*3*1 = 12 last digit 5: 4*4*3*1 = 48 last digit 0: 4*4*3*1 = 48
*April 7, 2016*

**Mathematics**

17+20-32 = 5
*April 7, 2016*

**Math**

If x bought 2 shirts and y bought only 1, then x = 120 9(2x+y) = 5(2x+y+120) + 1288 y = 232
*April 7, 2016*

**calculus**

a = (70-15)/15 = 11/3 km/hr/s Convert that to m/s^2, and then use s(t) = 15km/hr * 15s + 11/6 km/hr/s * 15s^2 = 15km/hr * 15/3600 hr + 11/6 km/hr/s * 15s * 15/3600 hr = 225/3600 + 11/6 * 225/3600 km = 17/96 km or 177 m Don't like mixing up all those units? 15km/hr = 4.167 ...
*April 7, 2016*

**calculus**

a(t) = -32 v(t) = 79 - 32t h(t) = 4 + 79t - 16t^2 Now just find the vertex of that parabola, at t = 79/32
*April 7, 2016*

**Calculus**

If each square has side x, then x = √200, and the total fence is 7√200 m I feel that the two areas are in fact not squares, but rectangles. In that case, if each rectangle has dimensions x by y, and they are separated by a side of length x, then the total fence is ...
*April 7, 2016*

**Math**

it's the same as just placing 3 balls in a row. 6P3
*April 7, 2016*

**math**

(2sinA+1)/(cosA+sin2A) = (2sinA+1)/(cosA+2sinAcosA) = (2sinA+1)/[cosA(1+2sinA)] = 1/cosA = secA
*April 6, 2016*

**Math**

no idea how to parse that. try writing things like 5c^3 or (5c^-3)/(y^4) using one line instead of all those lines.
*April 6, 2016*

**Math**

Since f is only defined on [-8,4] g(x) is only defined on [4,-2]=[-2,4] That is, g(-2) = f(4) and if you try to evaluate g(-3) = f(6) that is not defined. Play around a bit and you'll see that the domain of g is that of f, divided by -2.
*April 6, 2016*

**math**

the ball is at the top of the building to start with. At t=0, the ball is kicked. So, the last term, 146, is the height of the building.
*April 6, 2016*

**math**

well, what is h when t=0?
*April 6, 2016*

**Algebra**

12s+4c = 15 4s+12c = 21 now just solve for s and c.
*April 6, 2016*

**Algebra**

base * height = 96
*April 6, 2016*

**Math**

well i found it, i guess its 456=24t+264, as it gives t=8
*April 6, 2016*

**Math**

p=24t+264? is that right?
*April 6, 2016*

**Math**

Ty is reading a book that is 456 pages. In the last 11 days, he has read 264 pages. If Ty continues to read at the same rate, write an equation that represents the relationship between the number of pages, p, Ty reads over time, t.
*April 6, 2016*

**Geometry**

think about it. The original area is 1/2 bh The new area is 1/2 (3b)(h/3) = 1/2 bh no change.
*April 6, 2016*

**Math/Stats**

enter your data at http://davidmlane.com/hyperstat/z_table.html play around there for a while and it all becomes clearer.
*April 6, 2016*

**maths polynomial help!!!!**

x^2+2x+1 is (x+1)^2 So, do a synthetic division twice by x+1 and you get remainders of c-b and c-2b-a Both those remainders must be zero, so b=c and a+b=0 So, a can be anything, and b=c = -a and you have ax^3 + ax^2 - ax - a = a(x^3+x^2-x-1) = a(x+1)^2 (x-1)
*April 6, 2016*

**Math**

your answer is right, but you should have divided by 9. 5lb * 16oz/lb * 1apple/9oz = 8.8 apple make sure the units cancel correctly
*April 6, 2016*

**math**

4 2/3 + 3 1/3 = 8 oz Now, 40 = 8*5, so he needs 5 times as much of the paints.
*April 6, 2016*

**Algebra II**

#1 c #2 38400/32000 = 1.2 46080/38400 = 1.2 55296/46080 = 1.2 so, in 2015 it will be 55296* 1.2^9
*April 6, 2016*

**Algebra II**

#1,2 - just plug in a value for n #3 Tn = -62 + 15(n-1) = -77+15n #4 Tn = 1/243 * 3^n
*April 6, 2016*

**math**

depends on the wheel's radius. s = rθ all you have said is that s=10.
*April 6, 2016*

**Algebra**

from A to B at speed s took h hours. s*h = 400 on the way back, s*2 + (s+10)(h-2 - 1/3) = 400 h=5, so A to B took 5 hours. so, ...
*April 6, 2016*

**Math**

#1 D assuming the translation moves the 1st point to the 2nd. #2 ok #3 Having gotten #2 right, how can you choose what you did here?
*April 6, 2016*

**Math**

looks good
*April 6, 2016*

**maths**

see http://www.jiskha.com/display.cgi?id=1459708965
*April 6, 2016*

**math**

#1 just plug in various values for n. #2 note that as x increases by 2, y decreases by 1. So, you'd expect something like y = -1/2 x But, -1/2 * 2 = -1, and y = 1, so adjust the rule to be y = -1/2 x + 2 #3 just multiply 159 by the number of seconds.
*April 6, 2016*

**Math**

red = 4 green = 1/4 * 4 = 1 blue = 6*1 = 6 total: 4+1+6 = 11
*April 5, 2016*

**Math**

gotta know how many windows and their size.
*April 5, 2016*

**math**

the money is divided into two parts, in the ratio 12:10 So, 12x+20x = 9152 x = 416 So, Dande gets 12*416=4992 Mani gets 10*416 = 4160 total: 9152
*April 5, 2016*

**Calculus**

sounds like you want f'(x) = x e^(.01x) since you say that's the growth rate. So, the total number of computers for 20 years is the integral from 0 to 20 of f'(x) dx To do the integral, use integration by parts.
*April 5, 2016*

**math**

32°33' - 10°54' = 31°93' - 10°54' = 21°39'
*April 5, 2016*

**math**

and did someone say it was?
*April 5, 2016*

**math**

what, no calculator? Hint: 25^2 = 625
*April 5, 2016*

**math**

(3/8 * 1/4) / (3/4 + 1/5) = (3/32) / (19/20) = 60/608 = 15/152 As written, using PEMDAS and treating the fractions as single units, 3/8 * 1/4 / 3/4 + 1/5 = 3/32 / 3/4 + 1/5 = 1/8 + 1/5 = 9/40
*April 5, 2016*

**PHYSICS. HELP!my work**

Using the law of cosines, and the fact that adjacent angles of a parallelogram are supplementary, r^2 = 20^2 + 34^2 + 2*20*34 cos35° r^2 = 2670
*April 5, 2016*

**Math(1 question plz help thanks!=D**

C -2 and 2 have the same absolute value But 2 and 2 have the same absolute value
*April 5, 2016*

**Algebra**

If the fast plumber takes x hours, then the slow one takes x+5 hours. 1/(x+5) + 4(1/x + 1/(x+5)) = 2/5 x = 20 So, the 1st plumber takes 25 hours. Check: In 1 hour, the 1st plumber finishes 1/25 of the job. During each of the next 4 hours, the two together finish 1/25 + 1/20 = ...
*April 5, 2016*

**Maths**

If there are x behind, the queue looks like x ... me ... x+n (x+1+x+n) = 3x 2x+n+1 = 3x x = n+1
*April 5, 2016*

**Math**

(5/2)(3) = (1/2)(5)h h = 3
*April 5, 2016*

**Math**

(x-2)^2 + x^2 = (x+2)^2 2x^2-4x+4 = x^2+4x+4 x^2-8x=0 x = 0 or 8 0 is out, so the sides are 6,8,10
*April 5, 2016*

**College Algebra**

I think there's a typo. As written it is just 20 e^-t Anyway, since I have no idea when the plague began, I have no value for t. As for B, the typo does not allow for a limiting population.
*April 5, 2016*

**Math**

reflection through the y-axis changes the sign of the x-coordinate. Surely your text explains this. Or, you could get out some graph paper and do some experimenting. Just plot a point and flip it over the y-axis.
*April 5, 2016*

**Math**

how many times you gonna beat this dead horse?
*April 5, 2016*

**Maths**

if the cone were complete, it would have height 45/2, so the missing part has height 27/2. So, if there are x coins, (π*0.2*1^2)x = π/3 (5^2*45/2 - 3^2*27/2) x = 735
*April 5, 2016*

**Maths**

50 cot30° + 50 cot45°
*April 5, 2016*

**math**

surely it is 311*196=60956 or, as an estimate, 300*200 = 60,000 I guess their estimate is based on the average number of words per page. So, 60956 is close to 61,000.
*April 5, 2016*

**Math**

That is true. So, I guess your answer is ok, if you wanted it in ft^3. You neglected to mention that fact in stating the problem, or in giving units in your answer.
*April 5, 2016*

**Math**

how did 24 become 2?
*April 5, 2016*

**math**

It is in fact one of them. So, how do you use what I told you to get the whole population?
*April 5, 2016*

**math**

42/90 = 46.67% of the tagged squirrels. so, you can expect that 630 = 46.67% of the total population.
*April 5, 2016*

**Math**

looks good.
*April 5, 2016*

**Science**

Your answer makes no sense. The atom contains all three shells. Na is element #11. I think you omitted the question you are answering using the given data. (And I suspect it is shell 3)
*April 4, 2016*

**Algebra**

I'd say it's two positives & two negatives numbers on a number line in order of their absolute values from greatest to least
*April 4, 2016*

**Math Algebra 2**

something wrong with Reiny's previous solution? http://www.jiskha.com/display.cgi?id=1459772906
*April 4, 2016*

**Geometry**

google's first hit answers your question. Too bad you couldn't be bothered. https://www.algebra.com/algebra/homework/Bodies-in-space/Bodies-in-space.faq.question.975480.html
*April 4, 2016*

**Math**

any number.
*April 4, 2016*

**Math HELP!**

the law of cosines says that if x is the longest side and θ is the opposite angle, x^2 = 10^2 + 29^2 - 2*10*29 cosθ If x is less than 10^2+29^2, all three angles are acute. Of course, if x is not the longest side, then rearrange the numbers a bit to find other ...
*April 4, 2016*

**Math**

4/3 is greater than 1. So, how can 4/3 * 3.14 be less than 3.14?
*April 4, 2016*

**algebra**

you need to plug in the values and see whether they work on both lines. What do you get?
*April 4, 2016*