Saturday

October 10, 2015
Total # Posts: 34,468

**Algebra 2**

5r+4 <= 5 5r <= 1 r <= 1/5 I assume you can graph that on the number line.
*September 3, 2015*

**sjpuc**

If the swimmer's speed is s and the water's speed is w, we have s+w = 60 s-w = 8 I think you can now find s and w, no?
*September 3, 2015*

**Algebra. Please check my answers**

4^5 means 4 to the 5th power, or 1024 I suspect you meant something else. -(12x-8y) means -1(12x-8y) so you must use the distributive rule: -(12x-8y) = (-1)(12x) + (-1)(-8y) = -12x+8y So, (C) Your answer simply ignored the outside minus sign. It is the same as +(12-8y)
*September 3, 2015*

**Algebra**

#1 ok #2 ok, since 6/(x+y) isn't in the list #3 nope. What does quotient mean?
*September 3, 2015*

**MATH**

what does nCr4 mean? Try writing things as C(n,r+2) etc to make the arguments clear.
*September 3, 2015*

**math**

better check again. The pieces are 1'3" 2"6" 4'12" 8'24" add them up. Or, using a geometric series, the total is 1.25(2^4-1) = 18.75
*September 3, 2015*

**physics**

clearly a = (12rad/s)/(3s) = 4 rad/s^2 As with linear motion, s = 1/2 at^2, so it traveled through 1/2 * 4 * 9 = 18 rad
*September 3, 2015*

**Math. Check my answers**

6D (distributive property) 12B |-8| = 8 and |-10| = 10. 8 < 10 The others are all ok.
*September 3, 2015*

**math**

The tens digit must be even, since the hundreds is 1/2 of it. with the ones digit greater, that leaves 128 or 245 I suspect a typo.
*September 3, 2015*

**Math**

In that case, you made a mistake b^2 = 0.0063^2 = 0.00003969 4ac = 4(.00013)(-4.7) = -0.002444 b^2-4ac = 0.00248369 √(b^2-4ac) = 0.04984 (-.0063+0.04984)/.00026 = 167.45 (-.0063-0.04984)/.00026 = -215.91
*September 3, 2015*

**math please help!!**

The depth at midline is 7.9+1.1 = 9.0 f(t) is at midline at t=0, so you want a sine function, not cosine, which starts at a max. So, f(t) = 9.0 ± 1.1 sin(π/2 t) I use ± because they don't say whether the water is rising or falling at t=0.
*September 3, 2015*

**calculus**

sine or cosine, since (sin x)" = -sin x (cos x)" = -cos x So, (D)
*September 3, 2015*

**Math**

24:36 = 2:3, so each bag must contain at least 2 candles and 3 bottles. Can you take it from there?
*September 3, 2015*

**Math**

express everything in terms of meters: (7m)(2m)(0.1m) = 1.4 m^3
*September 3, 2015*

**Algebra**

original dimensions are w and 4w 4w-18 = w+18 Now you can find w, and 4w.
*September 2, 2015*

**Math**

just add a and b If c is negative, adding it is the same as subtracting its absolute value a+b+c = a+b-|c| That is, adding a negative value is the same as subtracting an equal positive value.
*September 2, 2015*

**math**

30 and 90
*September 2, 2015*

**Math**

-15 < 25
*September 2, 2015*

**math redux**

see related questions below
*September 2, 2015*

**Math**

think about it. A smaller pulley has to turn faster to convey the same amount of rope. Two pulleys of radii r1 and r2 move the same amount of rope if their speeds s1 and s2 are such that r1 * s1 = r2 * s2 Now just plug in your numbers
*September 2, 2015*

**Math**

SN is very good at expressing large numbers in a succinct manner, without having to count all those digits.
*September 2, 2015*

**Algebra 2**

The radius is 68, so the center is at y=68+14=82 x^2 + (y-82)^2 = 68^2
*September 2, 2015*

**algebra**

because it can be written as 57/100, the ratio of two integers. Any terminating decimal can be written in this way, as a fraction with the denominator a power of 10.
*September 2, 2015*

**Math**

there is a vertical asymptote when the denominator is zero. Since x^2+8 is never zero, there is no asymptote. Trick question.
*September 2, 2015*

**math**

I would assume you just replace all the r's with 1, and all the s's with 5: 2(5^3)-4(1^2) = 2(125)-4(1) = 250-4 = 251 Just plug and chug. I assume the arithmetic does not cause problems...
*September 2, 2015*

**algebra**

100m/11s * 1mi/1609m * 3600s/hr = 20.3 mi/hr Just keep track of the units, and use the conversion factors that make them cancel out the way you want.
*September 2, 2015*

**help please with math thanks**

You sure use a lot of words. Try using these characters in the future. If you can't recall the alt-codes, you can always find them and copy/paste them. #1 a. 3 + 2 b. √19 + 7/2 c. 18/3 + 11/10000 Your answers look good. I would have chosen 2C, but maybe you have been...
*September 2, 2015*

**Algebraic word problem**

We have: f = 5p p = 2m f+2 + p+2 + m+2 = 58 5p+2 + p+2 + p/2+2 = 59 Hmmm. I don't get an integer answer. Inspect problem for typos, and double-check my math.
*September 2, 2015*

**math**

h+|-8| = 15 h+8 = 15 h = 7 Looks like you need to review your absolute value function.
*September 2, 2015*

**calculus**

what, you have forgotten your 1st and 2nd derivative checks? And geez, this is one of your basic trig functions. You already know where the max/min/inflections are, so it's easy to check your answers. y = cosx y' = -sinx y" = -cosx y'=0 at all multiples of &#...
*September 2, 2015*

**calculus**

you know that v = π r^2 h, so h = v/(πr^2) the area is a = 2πr(r+h) = 2πr(r + 11.3/(πr^2)) = 2πr^2 + 22.6/r for minimum area, da/dr=0, so da/dr = 4πr - 22.6/r^2 = (4πr^3-22.6)/r^2 da/dr=0 when 4r^3-22.6=0, or r=1.216 The diameter d = 2r.
*September 2, 2015*

**math**

If her average now is x, then her total points so far are 4x. So, we have (4x+70)/5 = x-4 x = 90
*September 2, 2015*

**trig**

since A+B+C=180, A=70° Now use the law of sines to find c: c/sinC = a/sinA c/sin48° = 18.2/sin70° c = 14.4
*September 2, 2015*

**Biology**

Of the following, which is the most likely consequence of a manufacturing plant dumping its chemical waste into a nearby stream? increased oxygen levels in the water decreased flow rate of the stream loss of a keystone species an algal bloom <- my answer My question is ...
*September 2, 2015*

**Math**

what about 33 and 44?
*September 2, 2015*

**PHYSICS**

the crumpling bumper absorbs some of the impact, transmitting less force to the riders inside the car.
*September 2, 2015*

**physics**

The mass m does not matter. It takes about 1 second to fall 5 meters (using g=10m/s^2). Since v = at, that means v = 10 m/s
*September 2, 2015*

**calculus**

Looks like (a) to me. Assuming no typo in the equation.
*September 2, 2015*

**Math**

why bother with that? If the area is given in yd^2, just give each side in yd. √520 = 22.8035... So, each side is about 22.8 yd Now, if they wanted the dimensions in feet, then you'd divide the area by 9, since each yard is 3 ft, but you would certainly not divide ...
*September 2, 2015*

**Math**

If B's speed is x, the A's speed is x+53 Since distance = speed*time, we have 4.25(x + x+53) = 4568.75
*September 2, 2015*

**AP Algebra**

I also get 217.261 cm/s No idea what kind of rounding error produced 217.32 AAARFGBGGHH!! The Greek letter is pi</b not PIE! 4/3 π (4.6cm)^3 = 410 cm^3 Since mass = volume * density, that would be 410 cm^3 * 7.9 g/cm^3 = ...
*September 1, 2015*

**Mystery number**

Oh, wait. I misread the 2nd clue. It just means that both those digits are the same, since it said "value".
*September 1, 2015*

**Mystery number**

Just work through the instructions. I'll get you started, but I'm sure you can read as well as I. Start with xxx,xxx,xxx The digit in the tens place is the value of any number times zero. xxx,xxx,x0x The value of the hundred-thousands place is ten times the digit in ...
*September 1, 2015*

**Geometry**

(w+3)^2 = w(w+3)+54 w=15 So, the original rectangle was 15x18
*September 1, 2015*

**math**

c'mon -- that's just the difference of two squares, so you have (9-4x)(9+4x)
*September 1, 2015*

**math**

6x^3+14x^2-27x-63 2x^2(3x+7) - 9(3x+7) (2x^2-9)(3x+7)
*September 1, 2015*

**math**

well, just triple each dimension (11*3)(4*3) = (11*4)*3^2 since area involves two dimensions, it scales as the square of the linear dimension Perimeter, being just length, just uses the scale factor 2(3*11+3*4) = 3*2(11+4)
*September 1, 2015*

**Math**

h/83.2 = 5.8/2.5
*September 1, 2015*

**Math**

You just have to remember that dividing a number by itself gives a quotient of 1. When it says "solve for x" that means you want to find the value of x all by itself. SO, if you have -6g = 42 You just need to divide by the -6 to get g all by itself. Since -6g = 42, -...
*September 1, 2015*

**Pre-Calculus**

the roots are where g(x) = 0. So, you want 2x-5 = 0 x = 5/2 two lines are perpendicular if their slopes are negative reciprocals. That is, if line P has slope p, and line F has slope f, p*f = -1 Your first two answers are correct.
*September 1, 2015*

**Math**

math is ok, but intervals have the smaller value first. Also, you have a closed interval, since it's ≤ and not <. So your interval is [-2,-5/3]
*September 1, 2015*

**Math**

find t when 25 + 12t - 5t^2 = 3 using g=10 (easier than using 9.81)
*September 1, 2015*

**math**

The largest value is when x and y are almost equal: 10*11 The smallest value is when they are as different as possible: 1*20
*September 1, 2015*

**Math**

long piece is 6*7 other piece is 6*4 Maybe you can massage that into RDW.
*September 1, 2015*

**math**

what about that minus sign?
*September 1, 2015*

**Algebra**

x/y * y/x = 1 y*y*y*y*z = -16 x*y*y*z = 12
*September 1, 2015*

**Math**

both yes.
*September 1, 2015*

**Math**

wow. I suspect a typo. (1 1/10)/(1 1/5) = (11/10)/(12/10) = 11/12 So, you need 11/12 of 2 1/3 = 11/12 * 7/3 = 77/36 = 2 5/36 cups of milk. Mathematically precise, but not easy to measure. Luckily, 1/32 cup is 1/2 tbsp, so it can be done accurately.
*September 1, 2015*

**Algebra**

right on.
*September 1, 2015*

**Algebra**

generally, one says, "What is the product of x and y?" meaning x times y. A product, like a sum, needs two values. You give a single term, so I'd have said what is the value of (-6.8)^2 ?
*September 1, 2015*

**Algebra**

The math is correct. The grammar, not so much...
*September 1, 2015*

**Maths**

note that if the height is h, h*cot24° - h*cot38° = 300 Now just find h.
*September 1, 2015*

**algebra**

I'll assume you mean 1/(5/(x-1)+(3/x)) That would be x(x-1)/(8x-3)
*September 1, 2015*

**Applied Maths 1**

so, what about it? It's an interesting surface: http://www.wolframalpha.com/input/?i=1%2F%28sin%28x^2%2By^2%29%29^%281%2F5%29
*September 1, 2015*

**algebra 2**

Not sure any other version would be simpler, but if you want to get rid of the parentheses, (4xy^2)^-3 = 1/(4xy^2)^3 = 1 / 64x^3y^6
*September 1, 2015*

**Maths**

Let x = arctan(1/3) y = arctan(2/5) A+B = x A-B = y 2A = x+y tan2A = tan(x+y) = (tanx+tany)/(1-tanx*tany) = (1/3 + 2/5)/(1-(1/3)(2/5)) = 11/13 do 2B the same way
*September 1, 2015*

**devi**

or, if the "it" refers to the original amount, then 3/4 - 2/3 = 1/12 of the original amount on the dress.
*September 1, 2015*

**devi**

1/2 + 1/6 = 2/3 so, she spent 1/3 of the 3/4, or 1/4 of her original pocket money on the dress.
*September 1, 2015*

**TC**

Since sin(π-x) = sin(x), sin 7π/8 = sin π/8 sin 5π/8 = sin 3π/8 But your equation is clearly false, since all those sin^2 are positive, so they cannot add to zero.
*September 1, 2015*

**math**

the numbers are x and 2x+9, so x(2x+9) = 161 Now just solve for x. Or, note that 161 = 7*23, which fit the conditions above. You'd have had to figure that out to factor the quadratic anyway.
*September 1, 2015*

**Maths**

so, did you draw your diagram? Just start filling in the spaces.
*September 1, 2015*

**math**

y' = 1/x ds^2 = 1+y'^2 = 1 + 1/x^2 s = ∫[1,√8] √(1 + 1/x^2) dx wow - see what wolframalpha came up with: http://www.wolframalpha.com/input/?i=%E2%88%AB[1%2C%E2%88%9A8]+%E2%88%9A%281+%2B+1%2Fx^2%29+dx http://www.wolframalpha.com/input/?i=arc+length+ln%...
*September 1, 2015*

**Math**

as long as you came back, why did you not consult the related questions below?
*August 31, 2015*

**8th grade math**

9*6 = 54 beads used
*August 31, 2015*

**Physics**

3/2 the mass, 2/3 the acceleration.
*August 31, 2015*

**Geometry**

Assuming your math is ok as far as it went, have you not learned the quadratic formula? Use it, or solve by completing the square: x^2-x-14 = 0 x^2-x = 14 x^2 - x + 1/4 = 14 + 1/4 (x - 1/2)^2 = 57/4 x = 1/2 ±√(57/4) x = (1±√57)/2
*August 31, 2015*

**Algebra**

16/x
*August 31, 2015*

**Math**

22*4 + 15*6 - 3 - 134 = 41
*August 31, 2015*

**Algebra 2**

Looks like 5 hours to me. (2 hrs + 3 hrs) I suspect there is more to this question ...
*August 31, 2015*

**Algebra 2**

There is a nice elimination calculator online. It will show you all the details. http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
*August 31, 2015*

**Math**

let's use 13 numbers, so the median will be the center value. So, we start with x x x x x x 5 x x x x x x range and max: 2 x x x x x 5 x x x x x 8 mode 6: 2 x x x x x 5 6 6 6 6 7 8 others: 2 3 3 3 4 4 5 6 6 6 6 7 8 as long as there are more 6's than other values, ...
*August 31, 2015*

**math**

could be. You don't provide much context...
*August 31, 2015*

**Calculus**

d = 5t, so 6/s = 15/(5t+s) 6(5t+s) = 15s 30t = 9s s = 30/9 t
*August 31, 2015*

**precalc**

all are ok, except #5 should be y+4 = 2/3 (x+1) It makes a difference!
*August 31, 2015*

**precalc**

these are all point-slope problems. #3: y=4x-3 has slope 4, so your line has slope -1/4, and its equation will be y-1 = -1/4 (x-3)
*August 31, 2015*

**Math**

some negative numbers, like -3 and -1000 are integers. Others, like -2/3, -3.14 and -√7 are not
*August 31, 2015*

**spanish**

There's a tutoring web site called WyzAnt.com which helps find tutors in your area, in lots of different subjects.
*August 31, 2015*

**Algebra**

geez, guy. Can't you subtract 4 and check the result?
*August 31, 2015*

**Algebra**

Better go back to #3 and look again. The others look ok.
*August 31, 2015*

**Math**

Should show your work. Let the points (0,0), (2,1),(1,3) be A,B,C AB has slope 1/2 AC has slope 3 BC has slope -2 So, AB and BC are perpendicular. So, rotate the triangle about AB or BC AB is the line y = 1/2 x or x=2y BC is the line y = -2x+5 So, A is the correct answer. ...
*August 31, 2015*

**Math**

Find which two sides are perpendicular. Rotate the triangle about one of those sides.
*August 31, 2015*

**Algebra**

Let the smallest angle be x. Then, since the three angles add up to 180, x + (4x) + (4x-36) = 180 Now find x, and you can figure the angles.
*August 31, 2015*

**Algebra-domain**

x ∊ (-∞,-5)U(-5,6)U(6,+∞)
*August 31, 2015*

**Geometry**

you know the Pythagorean Theorem, right? The hypotenuse is the distance between A and B. The horizontal distance from A to B is (7-1) The vertical distance is (-7-1) Using the Pythagorean theorem, the length of the hypotenuse (the distance AB) is √((7-1)^2 + (-7-1)^2) = 10
*August 31, 2015*

**math**

try grouping: x^3-4x^2 -4x+16 x^2(x-4) - 4(x-4) (x^2-4)(x-4) (x-2)(x+2)(x-4)
*August 31, 2015*

**Geometry-Help Please**

use the edge to construct an arbitrary angle, with vertex at O. Mark an arc through the sides of the angle. Let the arc intersect the rays at A and B. Continue the arc on past B for a distance. Set the compass at B, and to the width of AB. Still with the compass at B, mark an ...
*August 31, 2015*

**math(algebra)**

since time = distance/speed, 40/(15+s) = 25/(15-s) Now just find s, the stream's speed.
*August 31, 2015*

**Math**

The area is 12(11+25)/2
*August 31, 2015*

**math,accounts,economics**

surely an accountant, eh?
*August 31, 2015*

**Math**

It's easier if you let u=4^x. Then 4^(x+1) = 4*4^x = 4u and you have u = 10-4u 5u=10 u=2 4^x = 2 but, 2 = √4 = 4^(1/2), so x = 1/2
*August 31, 2015*