# Posts by steve

Total # Posts: 52,313

math
If he can buy x expensive pencils that cost p each, then xp = 1800 (x+12)(p-40) = 1800 so, since x = 1800/p, (1800/p + 12)(p-40) = 1800 Now just solve for p

Maths
If you check this out, you will see that the velocity vectors form a right triangle, making things pretty easy. The final speed is just the hypotenuse of the triangle: ?(20^2+5^2) = ?425 ? 20.6 km/hr The direction is just (136-?)° where tan? = 5/20 the distance is of ...

WIS
80

english II
Shelby started what? direct object now what is "running" ?

Math
using a common denominator of 84, they are 42/84, 56/84, 32/84 so, what do you think?

math
A. if x is cut from each corner, then each side of the square base is 28-2x. When the tabs are folded up, the height of the open box will be x. As you know, volume is length*width*height B. The area (outside only) is the area of the square base plus 4 sides of length 28-2x and...

Pre-Calculus 12
well, you need to get the x stuff isolated, so get rid of those exponents: (x-2) log3 = x log5 x(log3-log5) = 2log3 x = 2log3/(log3-log5) = log9/log(3/5) = log3/59

Math
why stop there? subtract the equations and you get 2b = 10 b = 5 so, a = -4 so, the equations is -4x^2+5x+3 = 0 as always, the axis of symmetry is at x = -b/2a, so it is x = 5/8 and the vertex is at (5/8,73/16) you can see this by writing it as y = -4x^2+5x+3 = -4(x^2 - 5/4 x...

Trigonometry
as usual, parentheses make a big difference. sina/(1+cosa) if you recall your half-angle formulas, you know that this is just tan(a/2)

Algebra
you'll get a better answer if you don't forget that "-1" on the right: [x(x+1)] + [(x-1)(x-2)] = -(x-2)(x+1)

physics
since there is no acceleration, there must be some friction.

English
#1 is bad English -- improper grammar #2 is grammatical, but not something I'd say #3 is best, because it offers an accomplishment as proof of intelligence.

Math
just to get you started, 2x^2 + 7x - 15 = (2x-3)(x+5)

math
yes. just review your text on the topic of independent events.

Math
2/1887893279

math
assuming integer dimensions, 36 = 2*2*3*3 4x3x3: area=66 1x1x36: area=146

Math
It is neither arithmetic nor geometric. Take a look at the first few terms: T1 = 5^1/(2*3) = 25/30 T2 = 5^2/(3*4) = 25/12 T3 = 5^3/(4*5) = 25/4 ... As wolframalpha shows, the general sum is not elementary: http://www.wolframalpha.com/input/?i=sum+(r%3D1..n)+5%5Er%2F%5B(r%2B1)(...

math - incomplete
a curve has area zero, regardless of it radius. It's just a line.

Math
If a box's base measures x by y cm, and its height is h, then all we can tell is that v = xyh You don't give enough information to pin down any one of the three variables.

Maths
In that case, look for a typo somewhere. The numbers you gave produce the given result.

Maths
the modulus of z1 = |2-i| = ?(2^2+1^2) = ?5 z1•z2 = (2-i)(-2+i) = -3+4i so, Re(z1•z2)/?5 = -3/?5

math
a) 2x-3y = 1 kx+5y = 7 There is no single value of k which determines a unique solution. In fact, since the slope of 2x-3y=1 is 2/3, any value of k which makes the slope of the other line different from 2/3 will work. So, if -k/5 = 2/3 then k = -10/3 and the line -10/3 x + 5y...

math
6000000 * 0.90^4

math
just start with the first piece of data and make things fit. Apparently you have a 5-digit number: xxxxx My hundred digits means nothing: xx0xx and take it from there.

Math
Thanks for the referral! :-)

Math
If you find this interesting, read about Gödel encoding, where each letter is a prime factor raised to a power. The nth letter is the nth prime to the power of the letter's place in the alphabet. For example, cat is represented by 2^3 * 3^1 * 5^20 You can see that the...

math
the domain of rational functions is all real numbers except where the denominator is zero since x^2-4x-5=0 when x = -1 or 5 ?(3-x) is undefined when 3-x < 0, its domain is x <= 3 so, the domain of f/g is (-?,-1)U(-1,3) because anywhere else either f or g or f/g is ...

math
I have no idea what (srt)x means. I'll take a guess it is sqrt(x) or ?x. If I got it wrong, maybe you can clear it up. h(x) = 5-1/?(x+1) g(x) = 1/?(x+1) f(x) = 5-x h(x) = (f?g)(x) = f(g) = 5-g = 5-1/?(x+1) If you need to fix things a bit, it should be clear now how to ...

Calculus
Since his swimming speed is so much slower than his walking speed, I am surprised that the angle is so small. also, 3*0.13533 = 0.406 So, I suggest that Ø = ?-arcsin(1/8) = 3.01626 The graph seems to confirm this: http://www.wolframalpha.com/input/?i=x%2F8%2Bcosx

Chemistry
2BrF3 -> Br2 + 3F2

chemistry
well, how many moles in 2.5g of Butane? then the # of carbons (4 per molecule) is #moles * 4 * 6.023*10^23

Chemistry
how many moles of toluene? a 100% yield would produce that many moles of benzoic acid.

math
no, the threads replace a smooth area with two sides of a groove. Two sides of a triangle add up to more than the third side.

math
one fund: (90+20+10)/200 = 120/200 no fund: 8/200

math
I assume P(Q) is the price. So, the revenue R(Q) = Q*P(Q) profit is thus R(Q)-C(Q) = Q(50-Q/10)-(0.05Q^2+2000) = -0.15Q^2 + 50Q - 2000 now just find the vertex of the parabola.

Algebra
7+3?(2?5)

Math/Probability

Precal12
but n^2 + n - 56 = (n+8)(n-7)

Physics
first, how long till they meet? Check to see when the heights are the same: 25t-5t^2 = 25-5t^2 Now use that value of t to get the height.

Math
2/5 + 1/3 = 6/15 + 5/15 = 11/15 that's how much she spent. So how much was left?

math
come on, guy -- do the math (65/12 + 12/7) -------------------- = ? (65/12 - 12/7)

English
Q1: no difference. The "with me" is implied -- how could you take him home with someone else? Q2: #1 and #2 are basically the same: close proximity at the time. #3 is a little more general, since they may not actually be physically nearby at all times.

math
(3/8 - 5/12) / 1/(-15/8 * 16/27) = (9/24 - 10/24) * (-15/8 * 16/27) = (-1/24) * (-10/9) = 5/108

Math, science.
consider the fact the two angles add to 180° so, what is the sum of their bisectors?

sjps science
sentence is gibberish no choices listed

Math
5588 6299 and others

algebra
cosA/(1-sinA) * (1+sinA)/(1+sinA) = cosA(1+sinA)/(1-sin^2A) = cosA(1+sinA)/cos^2A = (1+sinA)/cosA = secA + tanA You can easily see that your original equation is false. Just use A = pi/4

Math
C(x) = 40x

AOOOGAH!! Homework Dump!!
not here, buddy...

physics
by "length" do you mean the tread width? Otherwise, what difference does it make how long the step is? Anyway, just figure the distance to cover one step (up and across), and multiply by 5. then use the Pythagorean Theorem on the total horizontal and vertical ...

Math
think linear inertia resisting the centripetal force

plane geometry
well, r = s/?3

maths
Hmmm. I'd say that AC=8 Also, the 3rd side is either 8 or 12, right?

maths
what, no calculator? just enter the expression into google. Be sure to use enough parentheses. If you enter your text at wolframalpha.com, it will show you how it interpreted your input.

physics
v(t) = 20-10t Think on it. Each second, the velocity decreases by 10 m/s

geometry - incomplete
without a diagram, it is impossible to tell how the angles are related.

math
just write it as math, and then solve. If the AP has 1st term a, and the GP has first term g, then a+2d = g a+3d = gr a+7d = gr^2 10/2 (2a+d) = 85

circles
they are exactly the same equation.

Math
(1/2)^(10000/24000) = 0.74915 (1/2)^(30/n) = 4^(-1/3) n = 45

trigonometry
I did this one already, but your typo made it work out wrong. You have fixed the typo, so just change the 15 to 5, and work it out. What do you get?

Math
all three of these are basically the same. You have a constant value up to some value, then a linear function after that.

math urgent help
that's better.

math urgent help
almost. You forgot the 2x^2 f(-4) = 2*16+20-3

Math
2nd piece: f(d) = 8.00 + 1.50?d-4? for d>4 Now you should be able to provide the other piece.

plane geometry
I see you could not be bothered to study the url I gave you earlier. I'll do most of your work for you. the area of the triangle, found using the method of your choice, is 2310 so, the radius of the excircle is (68+75+77)/2 - 68 = 2310/42 = 55 thus, the circle's area ...

Math
this is an old and intractable problem. Read about the Traveling Salesman problem.

maths
try using the minus sign (-) instead of the underscore (_) for subtraction. 2x^2-3x-5=0 (x+1)(2x-5) = 0 ...

Math
72 = 8*9 64 = 8*8

Math
which one is a multiple of 9? go with that one.

maths
5008

Physics
The plane takes a heading, not a bearing. So, draw the velocity triangle. You should be able to see that speed: s = ?(250^2+50^2) heading: tan? = 50/250

maths
correct

Physics
30 minutes is 1/2 hour, so 70 km/hr * 1/2 hr = 70/2 = 35 km

Math
come on, give it a little thought. What is the largest digit? 9 so, now you have 9xxxxx work on the other sentences. they are all very easy.

Math
42

Physics

physics
as with all geometric objects, the volume grows as the cube of the linear scale factor. I assume your coefficient is 12*10^-6 cm/°K (can't quite tell from your notation). Anyway, if the linear size grows by 1.0002, then the area grows by 1.0002^2 and the volume grows ...

math
subtract the pool from the total to get the area of the walk: (15+2w)(10+2w) - 15*10 = 116 now just solve for w

Mathematics
t(m) = 300 for m <= 100 t(m) = 300+(m-100) for m > 100

science
since PV = kT (2P)(2V) = 4PV = k(4T) so, 4 times the (Kelvin) temperature

physics
F = ma, so a = F/m a1 = 72/m1 a2 = 72/(m1+m2) not sure whether the "same force" means the same 72N force, or another force of equal size. If the latter, then both forces acting together would impart an acceleration of (72+72)/(m1+m2)

Algebra
they are the same line, so ...

Clinical Calculations
well, 117/9 = 13, so that's 13 "doses" 500 mg/8hr = 1500mg/day Hmmm. we said he'd need 13 times the base amount

Math
just check the possibilities. You want two evens + an odd to add up to 11. 227 443

Math
try again, after fixing your typo.

trigonometry
this url shows how to figure the radius of an escribed circle. https://math.stackexchange.com/questions/1674656/radius-of-an-e-circle-in-terms-of-triangles-sides-and-area

trigonometry
you are just interested in the east-west distances traveled. When they are the same, B is north of A. So, t hours after A set off, you want (15 sin42.58°)t = (7 sin46.33°)(t-2) This has a solution of t = -2 huh? I suspect a typo. A is going twice as fast, for two hours...

trigonometry
If we call h = height of flagpole t = height of tower The four angles are x,y,a,b in the order named, then we have h/120 = tanx t/120 = tany x = 2y a+b = pi/2 that means that sin(a+b) = 1 That's a lot of equations to work with, but we know that tanx = tan 2y = 2tany/(1-tan...

trigonometry
bisect the base, and you can see that the two equal sides have length 6/sin40° proceed from there.

Maths
The interest earned each year is r/100 * 3500. So, after 3 years, the interest amounts to the amount of increase: 3500*3r/100 = 6020-3500

maths
pretty big box!

maths
the wood is the difference between the outer and inner volumes. In cm^3, that is 200*20*22.5 - (200-5)(20-5)(22.5-2.5)

math
not sure what all the extra punctuation means. But rounding off to thousands means ....(x-1)501 - ....x499 round to ....x000

Math
only 186 is a multiple of 6. So, \$2.85 * 186/6 = ?

Math
940 = 2^2 * 5 * 47 So the only choices are 2,5,10

lmatha
6300*1.07*(8/3)

math/statistics
If you made a Venn diagram, and remember how they work, then (a) (120+146+68)-(36+27+23)+x = 400-132 (b) now use the Venn diagram to add up the three parts that don't intersect any others.

math
sounds right, if you want your angle in degrees.

sir steve reiny bob damon need help maths
sure is hard to interpret your prose. If x is the input, then it appears that you are saying (16/25) * 1/(4x^2)*(1+12x/5) = 1 somewhere there should be a subtraction, since you use the word "difference" but I can't figure out what, unless maybe there's a (12/...

College - Unweighted GPA
total GPA It does not say anything about senior year only. Although, it occurs to me that my high school only reported my senior year's GPA. That's what HS counselors are for. Talk to yours.