# 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**

google is you friend. You might start here: https://www.quora.com/What-is-the-expected-number-of-coin-flips-until-you-get-two-heads-in-a-row

**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**

ever hear of google?

**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.