Wednesday

October 7, 2015
Total # Posts: 34,355

**math**

of a rectangle with width 2 and length 5.
*September 20, 2015*

**Math**

just use what you are given: 500p - p^2 >= 60000 Now, just from what you know about parabolas, you know that the parabola opens downward. So, the portion of the curve above a horizontal line (here, y=60000) will lie between the roots of 500p - p^2 - 60000 = 0 The roots are ...
*September 20, 2015*

**Pre-Calculus**

vertical asymptotes where the denominator is zero. I assume you can figure that out. Hint: don't bother expanding the denominator...
*September 20, 2015*

**7th grade math **

Product of hundreds and tens place is 1. clearly the 1st and 3rd digits are 1. So, the number is 171.
*September 20, 2015*

**Math**

solve for t in 10000(1.05^t - 1)/.05 = 1000000 or 1.05^t - 1 = 2000 ...
*September 20, 2015*

**Maths**

It's always true, since both sides are always positive or zero.
*September 20, 2015*

**math**

the marked price is 200(1.50) The discounted price is thus (200)(1.50)(1-0.25)
*September 20, 2015*

**algebra**

Assuming the restaurant is in NYC, that means that if the whole distance is x, 1 + x/2 + x/6 = x
*September 20, 2015*

**pre calculus**

At 10:00 the hands are 60 degrees apart. So, as soon as you decide how long the hands are, use the law of cosines to find the desired distance.
*September 20, 2015*

**Math**

since the ratio is constant, find the flagpole's height f, using f/12.8 = 1.8/4.32
*September 20, 2015*

**Math**

all of these problems are just direct variation. For this one, 20/200 = x/700 Now you try the others. Look for a constant ratio (direct variation)
*September 20, 2015*

**Geometry**

just add up the angles. If the 2nd angle is x, then x + 2x + x-20 = 180 Knowing x, you can surely find 2x.
*September 20, 2015*

**P6 maths**

neither do I. But, if the amounts of the tickets are x,y,z, then 12x = (12x+30y+50z)(1/4) 30y = (12x+30y+50z)(3/5) x = y+5 Clear the fractions and do some substitution, and you will find that z=18
*September 20, 2015*

**Calculus**

for the limit L to exist, |f(x)-L| < ε whenever |x| < δ But no matter how small δ is, there are points in the interval [0,δ] where f=1 and f=0.
*September 19, 2015*

**Math**

x = 3(180-x)-20 x = 130 so, the ratio you want is 130/50
*September 19, 2015*

**Logarithm help**

assuming all logs are in base 4, we have log 3 + log √8 - log 2 = log(3√8/2) = log(3√2) If, for some reason you are using logs base 10, and all the numbers are the values, then we have log 4^3 + log 4^4 - log 4^2 = log(4^3*4^4/4^2) = log(4^5) = log(1024)
*September 19, 2015*

**Math**

4-6x > -15+1 4-6x > -14 -6x > -18 x < 3 Looks good to me.
*September 19, 2015*

**math**

Since it says Solve by substitution.. y=4x-7 2x-3y=6 just substitute in 4x-7 for y in the 2nd equation: 2x-3(4x-7) = 6 2x-12x+21 = 6 -10x = -15 x = 3/2 y = 4x-7 = 4(3/2)-7 = 6-7 = -1 Paul's solution method is strange (and wrong). Using the intercepts will not help in ...
*September 19, 2015*

**math**

since time = distance/speed, x/50 = x/25 - 1/2
*September 19, 2015*

**MATH**

x/1/3 = 1/2 x/3 = 1/2 x = 3/2 Odd notation. Maybe you meant x/(1/3) = 1/2 3x = 1/2 x = 1/6
*September 19, 2015*

**MATH**

LCM(8,12,20) = 120 Now you can figure how many packs of each make 120
*September 19, 2015*

**MATH**

16*25 - 32*75/64*6*16 400 - 32*16*6*75/64 400 - 64*8*6*75/64 ... You must do all the multiplications and divisions before the subtraction.
*September 19, 2015*

**Geometry**

what is the sum of two right angles?
*September 19, 2015*

**Math**

I think I saw this as -12 / 3 * [-8 + (-4)^2 – 6] + 2 -4 * [-8+16-6] + 2 -4 * (2) + 2 -8 + 2 -6 If it really was as you typed it, then just change the numbers and evaluate in the order I used.
*September 19, 2015*

**Physics**

clearly, v=0 at highest point (ball stops and starts to fall) arrival speed = departure speed a = -9.81 always (gravity)
*September 19, 2015*

**Logarithm help**

come on - simple algebra: (1+x)/(1-x) = .4306765581 1+x = .4306765581(1-x) Think you can handle it now? How about 1+x = 3(1-x)
*September 19, 2015*

**Math**

the cars make up 15/19 of the total. I suspect a typo.
*September 19, 2015*

**Math**

the water is 1/6 of the total.
*September 19, 2015*

**statistics**

visit this web site and specify 0.50 for the area. It will give you the min/max values. http://davidmlane.com/hyperstat/z_table.html
*September 19, 2015*

**P6 maths**

If Raja has x, and Lee has y, then we are told: after d days, y-15(x/30) = 610 y-30(x/10) = 10 Solve for x and y, and you will get x+y=970
*September 19, 2015*

**Math**

looks ok to me.
*September 18, 2015*

**Math**

That's the answer mine gives.
*September 18, 2015*

**Logarithm help**

(1+x)(log 5)= (1-x)(log 2) (1+x)/(1-x) = log2/log5 = .4306765581 x = -0.39794
*September 18, 2015*

**Logarithm help**

see related question below
*September 18, 2015*

**physics**

43ft / (154ft/s) = 0.279s
*September 18, 2015*

**Computer program**

well, did you actually try running it?
*September 18, 2015*

**math**

2x3 -+4r2 makes no sense. However, 25^3 - 42^2 does indeed equal 13861
*September 18, 2015*

**Algebra**

-7 / (14/3) = -7 * 3/14 = -21/14 = -3/2
*September 18, 2015*

**math**

However, it's hard to say, since lots of folks online omit the ^ for exponents (-3)^4 = (-3)4 = 81
*September 18, 2015*

**Chemistry**

(e) 1.7777 -> 1.78 -> 2 I have no idea what if there over? means. In each case, round to 3 digits, then round that result to 1.
*September 18, 2015*

**Chemistry**

(a) 87.073 -> 87.1 -> 90 (b) 4.3621 -> 4.36 -> 4 and so on what do you get?
*September 18, 2015*

**Physics**

remember the law of cosines? the angle between the two headings is 55.4° So, figuring distance = speed * time, we have your distance apart (z) after 2.3 hours is z^2 = (730*2.3)^2 + (610*2.3)^2 - 2(730*2.3)(610*2.3)cos55.4° z = 1453 m I suspect you meant mi (miles), ...
*September 18, 2015*

**trigonometry**

Looks good to me.
*September 18, 2015*

**Logarithm help**

the fraction left after n pages is p(n) = 0.995^(n/10) Now you can use that to answer the other two parts.
*September 18, 2015*

**Logarithm help please**

If you mean log(4y) = x + log(4) Then you have log(4y/4) = x log(y) = x x = 10^y Assuming the usual lack of care with parentheses, I'll guess you mean 5^(1+x) = 2^(1-x) 5*5^x = 2 * 1/2^x (5/2) = 1/(10^x) 10^x = 2/5 x = log(2/5)
*September 18, 2015*

**calculus**

y = (x^2 sinx) / (x+2)(x^2-1) = (x^2 sinx)/(x^3+2x^2-x-2) Woah ... this will get messy d/dx (x^2 sinx) = 2x sinx + x^2 cosx d/dx (x+2)(x^2-1) = 3x^2+4x-1 y' = (2x sinx + x^2 cosx)(x^3+2x^2-x-2) - (x^2 sinx)(3x^2+4x-1...
*September 18, 2015*

**math**

Starting with x blooms, we have (1 - 3/14 - (2/5)(11/14))x = 66 33/70 x = 66 x = 140
*September 18, 2015*

**Physics**

the plane flies 445*1.97 = 876.65 km So, in still air, its position would be (270.9,833.7) So, you want Vx * 1.97 = 0-270.9 Vy * 1.97 = 785-833.7 Now you know Vx and Vy, so you can find V and its direction
*September 18, 2015*

**circle trigonometry**

sinθ = y/r So, in QII, y = 2 r = 3 x = -√5 Now, cosθ = x/r = ?
*September 18, 2015*

**Physics**

If we assume that the ball just grazes the hoop and somehow falls in, we can work it out like that. In real life, of course, the ball will rise above the hoop and fall in from somewhere above it, but since no such information was given, we have to just assume that y(0) = 0 y(8...
*September 18, 2015*

**Algebra**

clearly it is (C) since substitute means put in the place of
*September 18, 2015*

**mathematics**

well, which is it? 8 or 17?
*September 18, 2015*

**Math**

I think you used x for multiplication, rather than a variable. If not, then Shawn's solution finds the value of x which makes the equation true. I was under the impression you were just trying to evaluate an expression.
*September 18, 2015*

**Math**

-12/3x(-8+(-4)^2-6)+2 -4(-8+16-6)+2 -4(2)+2 -8+2 -6
*September 18, 2015*

**Math**

(1+.09/2)^(2t) = 3 Now just solve for t (years)
*September 18, 2015*

**Math**

(1+.05/12)^12 = 1.05116 So, that would be 5.116%
*September 18, 2015*

**Calculus**

a(s) = πr^2 = π(3√s)^2 = 9πs a(5) = 45π Don't forget your Algebra I now that you're taking calculus. You will be using it a lot!!
*September 18, 2015*

**Math**

159mi/3hr = 53 mi/hr
*September 18, 2015*

**PHYSICS**

v(t) = dx/dt = u+at Now go for it. I hope you have a value for a.
*September 18, 2015*

**science**

need to what? meditate? learn? rant? sing? dance? google is your friend...
*September 18, 2015*

**math**

just add up the interest on each part. If $x was at 8%, the rest (8000-x) was at 10%. So, .08x + .10(8000-x) = 700
*September 18, 2015*

**shaw**

mass
*September 18, 2015*

**physics**

well, 1J = 1N-m So, since you want meters, 42x10^6 N-m/500N = ? m
*September 18, 2015*

**math**

.20*.25*80 + .10*(1-.25)*80 ------------------------------- = 1/8 = 12.5% 80
*September 18, 2015*

**math**

I think you meant whole1
*September 18, 2015*

**Chemistry**

Looks ok to me.
*September 18, 2015*

**physics**

you want t when 2.5t^2 = 1800
*September 18, 2015*

**physics**

The horizontal speed does not matter. As you know, the max height is v^2/2g where v is the vertical speed. So, plug in your numbers.
*September 18, 2015*

**Science**

since F = GMm/r^2, twice the radius means 1/4 the force.
*September 18, 2015*

**Maths**

actually, 6840 is the Least common multiple. There is no greatest multiple.
*September 18, 2015*

**Maths**

120 = 2^3 3 5 180 = 2^2 3^2 5 190 = 2 5 19 So, take the highest power of each prime common to all numbers: 2 5 = 10 No other (larger) combination of those prime factors will divide all three numbers.
*September 18, 2015*

**algebra**

exclude values where the denominator is zero.
*September 18, 2015*

**Grade 11 math**

that would be 1.1/10.9
*September 17, 2015*

**Calculus**

(1-cotx)/(cosx-sinx) = ((sin-cos)/sin) / (cos-sin) = -1/sin --> -√2
*September 17, 2015*

**math**

2/(5m-14) = 9+3/(5m) That gets nasty. How about 2/(5m)-14 = 9+3/(5m) m = -1/115 probably not. How about (2/5)m-14 = 9+(3/5)m m = -115 Parentheses make a difference.
*September 17, 2015*

**Algebra 2**

√(120x^5y^4) √4√30 √x^4√x √y^4 = 2x^2y^2 √(30x) You were close, but changed a √2 to 2.
*September 17, 2015*

**Math**

integer
*September 17, 2015*

**math**

well, 6 min is 1/10 of an hour, so ...
*September 17, 2015*

**math**

draw a line of 3 squares. Now draw 8 more, so you wind up with 9 lines of 3. Or, 3 columns of 9
*September 17, 2015*

**math**

you can't "solve" a linear equation. It just describes a function. Now, if you want to see where the two functions are the same, you need x+4 = -2x+1 3x = 3 x = 1 so, y=5 If you want to find the root, where y=0, then just set y=0 and solve for x: 0 = x+4 x = -4
*September 17, 2015*

**algebra**

x + 5x+1 = 25
*September 17, 2015*

**Math**

You need the quadratic formula for this, since it does not factor over rational numbers. Now, 4x^2-4x+1 = (2x-1)(2x-1)
*September 17, 2015*

**8th grade math**

8.5 = 14 - 1/32 x 1/32 x = 14 - 8.5 1/32 x = 5.5 x = 5.5 * 32
*September 17, 2015*

**math**

I don't see any expressions; just sets of three numbers. Ahhh. If you mean 40.1 * 10^26 4.1 * 10^27 0.411 * 10^26 0.04001 * 10^25 then convet them all to 10^25 and you have 401 * 10^25 410 * 10^25 4.1 * 10^25 0.04001 * 10^25 Now it should be clear.
*September 17, 2015*

**Math**

700,000 -300,000 ------------- 400,000 That's low, because we rounded down the minuend and rounded up the subtrahend.
*September 17, 2015*

**prealgebra**

41/(35x)
*September 17, 2015*

**Math**

100,000 = 10^5 1,000,000 = 10^6 10^6/10^5 = 10 Or, just count the zeros. Subtract the zeros from the smaller number and see what's left of the larger number.
*September 17, 2015*

**Math**

convert each ratio to a decimal, then compare. For example, 35/84 = 0.417 laps/min now do the others
*September 17, 2015*

**Math**

2(w + 3w) = 80 w = 10 The garden is 10x30 Now you can find the area, and of course, the number of pavers. Don't forget the corners.
*September 17, 2015*

**Algebra 2**

What happened to your y's? Typo, I'd guess So far, so good: (1/27x^3)/ (1/y^9) = (1/27x^3) * y^9 = y^9/27x^3 Or, you could have done (3x/y^3)^-3 = (y^3/3x)^3 = y^9/27x^3
*September 17, 2015*

**chemistry**

CaO + 2HNO3 = Ca(NO3)2 + H2O
*September 17, 2015*

**math**

since distance = speed * time, If train #1's speed is x, 4x = 2(x+42)
*September 17, 2015*

**Algebra**

I think you will get a better result from (x + x+1)4=17 It's confusing if you use x for both multiplication and a variable. And, as we are looking for Frodo's rate, I'd use 4(f + f-1) = 17
*September 17, 2015*

**Maths**

There's a nice discussion of this topic at http://mathforum.org/dr.math/faq/faq.0.to.0.power.html Sorry -- it's turtles all the way down.
*September 17, 2015*

**Math**

3a(3a-2b)+b^2-c^2 9a^2-6ab+b^2-c^2 (3a-b)^2-c^2 (3a-b+c)(3a-b-c)
*September 17, 2015*

**mamacao elementary school**

clearly C=0 or 1 or 5 or 6 Probably not 0, eh? C cannot B 1, since then we must have ABC*1 = ABC. AB5*5 = DB5 AB6*6 = DB6 If A is more than 1, there will be a carry in A*5, so A=1 There is clearly a carry from B*5 or B*6, so 1B5*5 = 2B5 1B6*6 = 2B6 If C=5, B must be even. ...
*September 17, 2015*

**trigonometry**

Sitintile senior secondary school is not the subject. A tutor who is in a hurry or bored might just ignore a posting that appears bogus, or maybe posted by someone who cannot follow simple instructions. Did you draw a diagram? Review your basic trig functions, and you will see...
*September 17, 2015*

**analytic geometry**

Your font got garbled in the copy/paste. What is Î± supposed to mean?
*September 17, 2015*

**Intermediate Algebra (math)**

Well, since this is a fairly straightforward expression, just divide each term of the numerator by the denominator. Just as in (20+30+50)/10 = 20/10 + 30/10 + 50/10, you have (8x^2y^2+4xy^2-12y^2) ÷ 4xy^2 = 8x^2y^2/4xy^2 + 4xy^2/4xy^2 - 12y^2/4xy^2 = 2x + 1 - 3/x or, if...
*September 17, 2015*

**Math**

well, A = bh So, plug in your numbers and find b.
*September 17, 2015*