Tuesday

September 1, 2015
Total # Posts: 33,191

**ST MICHAEL NURSERY SECONDRY AND PRIMARY SCHOOL KONTAGORA**

force = mass * g work = force * distance power = work/time
*June 20, 2015*

**algebra**

Just use the distributive property: (3x+4)(x-2) (3x)(x-2)+(4)(x-2) 3x^2-6x+4x-8 3x^2-2x-8 Do #2 the same way Review the examples in your text, or google binomial multiplication
*June 20, 2015*

**Algebra**

from eq #1, you know y = 10-x substitute that into eq #2 and you have 5x-3(10-x) = 15 Now you can find x, and then y.
*June 20, 2015*

**Math**

you know: 7a+4.5c = 64 a = c-4 now just solve for a and c.
*June 20, 2015*

**ALGEBRA**

after each drain-fill cycle, there is 0.8 the amount of wine as before. So, after 20 cycles, the wine remaining is 20(0.8^20) liters
*June 20, 2015*

**Ndmc - redux**

Eh? I read it that the car passes the bus just as the bus starts to move. The car has constant speed, so at some point the accelerating bus will overtake the car. I haven't checked the math above, but the problem makes sense to me.
*June 20, 2015*

**algebra**

|4x+4| = 3 |x+1| = 3/4 x+1 = ± 3/4 x = -1 ± 3/4 x = -7/4 or -1/4 So, -1/4 is correct, as seen by using it: |4(-1/4)+4| = |-1+4| = |3| = 3 you can verify -7/4 for yourself.
*June 19, 2015*

**algebra - ouch**

I did check the other answer. Sure enough, √1 + 9 = 10 and I thought, "That's ok." Good catch. I had expected an extraneous root, and was surprised that there "wasn't" one.
*June 19, 2015*

**algebra**

Did you actually try using your values to see whether they satisfied the equation? √(10-x) + x = 8 √(10-x) = 8-x 10-x = x^2-16x+64 x^2-15x+54 = 0 (x-9)(x-6) = 0 x = 6 or 9 should have showed your work, so we could see what went wrong.
*June 19, 2015*

**Graduated :math**

I predict 67,07,71,69,76
*June 19, 2015*

**algebra 1**

standard form is Ax+By=C You can rearrange things to have 0.2x - y = 0.3 That's close, but we want integers. Now, how do you get rid of those pesky decimals?
*June 19, 2015*

**Probablity**

total marbles: 15 so, P(black,black) = 4/15 * 4/15
*June 19, 2015*

**math**

hint: any number ending in 0 or 5 is a multiple of 5.
*June 18, 2015*

**math**

actually, I get 14% The decrease was $11.71 11.71/80.77 = .1449 which is closer to .14 than .15 Pick 0.14 - 0.14 is 14% just expressed as a decimal. The wording is not optimal, but the two values are identical.
*June 18, 2015*

**statistics**

in your Z table you can easily find P(Z>1.05) also, P(Z>2.05) So, you just want P(Z>1.05) - P(Z>2.05) or, you do it the other way: P(Z<2.05) - P(Z<1.05) even easier, go to http://davidmlane.com/hyperstat/z_table.html and specify Z between 1.05 and 2.05 You ...
*June 18, 2015*

**Algebra 2**

1) x y d1 d2 d3 d4 0 8 1 7 -1 2 20 13 14 3 83 63 50 36 24 4 256 173 110 60 24 5 623 367 194 84 24 6 1292 669 302 108 24 Note how the 4th difference column is all 24 - 4th derivative of x^4 = 24 8^log_8(x) = x exponentiation and logs are inverse operations. b^log_b(x) = log_b(b...
*June 18, 2015*

**Math Geometry**

the sun rises 90° in 6 hours. That's 15°/hr So, at 11 am the angle of elevation of the sun is 75° If the shadow's length is s, then s/8 = cot75°
*June 18, 2015*

**geometry**

The area of all the exposed faces is 2(10*12 + 10*3 + 12*3) = 372 in^2 add to that the 7 in^2 of overlap.
*June 18, 2015*

**Maths**

8*6.50 + 4*2.10 ---------------------- 8+4
*June 18, 2015*

**System of Equation**

what methods of solution have you discussed?
*June 18, 2015*

**Math (Need help Urgent)**

#1 just solve for x in 4x-12 = -x^2+15x Then you can get y. #2 same thing. Just solve x^2-4 = 2x-4 to get x, then you can evaluate y.
*June 18, 2015*

**math**

you have to ask yourself. If a man can do the job in m hours, how much can he do in one hour? 1/m So, 2 men can do 2/m of the job in one hour. Same for the 6 boys. So, since they all can complete the job in 3 hours, in one hour they have done 1/3 of the job. You have to think ...
*June 18, 2015*

**math**

oops. I meant 9 men can do it in 2 hours.
*June 18, 2015*

**math**

2/m + 6/b = 1/3 1/m = (3/2)/b m = 18. That means one man can cut the field in 18 hours 2 men can do it in 9 hours
*June 18, 2015*

**Math (PLEASE HELP!)**

#1 eliminate y by equating the two: 2x^2-2x-3 = -x^2-2x-3 Now solve for x, and then you can get y #2 same thing #3 again, use the discriminant. We want kx^2-5x+2 = -3x+4 kx^2-2x-6 = 0 The discriminant is 4+24k
*June 18, 2015*

**Math (PLEASE HELP!)**

#1 well just solve -0.15(x-13)^2+7.6 = 7 just the usual quadratic stuff. #2 The discriminant gives this information. b^2-4ac: <0 no roots =0 1 root >0 two roots
*June 18, 2015*

**Math (PLEASE HELP!)**

(x+y)(x-y) = 24 x^2+y^2 = 74 you want some place where the tangent to the parabola has slope = -2 6x+4 = -2 x = -1 so, y=-2 The tangent line at (-1,-2) is y+2 = -2(x+1) y = -2x-4 b = -4 see http://www.wolframalpha.com/input/?i=plot+y%3D3x^2%2B4x-1%2C+y+%3D+-2x-4
*June 18, 2015*

**Algebra**

|z|^2-2z*+iz = 2i letting z = x+yi, x^2+y^2 - 2(x-yi) + i(x+yi) = 2i x^2+y^2-2x+2yi+ix-y-2i = 0 (x^2+y^2-2x-y)+(x+2y-2)i = 0 so, now just solve x^2+y^2-2x-y=0 x+2y = 2 x = 2-2y (2-2y)^2+y^2-2(2-2y)-y=0 5y^2-5y = 0 y = 0 or 1 so, x = 2 or 0 z = 2, i
*June 18, 2015*

**Calculus**

after t seconds, Q(t) = 9*0.996^t Now just solve for what you need.
*June 18, 2015*

**Math**

You want x where 3.00(x) + 4.25(8) = 4.00(x+8)
*June 17, 2015*

**math**

26 total marbles, so P(red,yellow) = 14/26 * 12/25
*June 17, 2015*

**math**

just divide both sides by 19.2L
*June 17, 2015*

**calculus**

It might help if you actually supplied the function. Clearly it looks something like -100x^2 --------------------- (x+10)(x-10)
*June 17, 2015*

**logical statements-urgent**

We want the truth table to look like this: PQR S TTT F TTF F TFT F TFF F FTT F FTF T FFT F FFF F Looks like it reduces to Q&~(P|R)
*June 17, 2015*

**math**

1/3 + 4/9 = 7/9 that help?
*June 17, 2015*

**physics**

this is one of the most basic setups. Clearly you need to do some reading. series: R = 1+2+3+5 = 11 parallel: 1/R = 1/1 + 1/2 + 1/3 + 1/4 R = 12/25
*June 17, 2015*

**Calculus**

Let side x be parallel to the barn. Then x+2y = 34 a = xy = (34-2y)y = 34y-2y^2 da/dy = 34-4y max area when da/dy=0, or y=17/2 So, the pen is 17 by 17/2 As usual, max area is when the fencing is divided equally among lengths and widths.
*June 17, 2015*

**Finite Math**

what do we know? if we let x = # dipped bananas y = # dipped apples z = # dipped strawberries so, to produce such a mix, we need 6x+6y+z = 60 3x+4y+z = 42 equating z, we wind up with 3x+2y = 18 So, let's see what we can do, using only integer values: x y z 0 9 6 2 6 12 4 3...
*June 17, 2015*

**Physics**

Recall that the range R = (v^2 sin2θ)/g so, just plug in your numbers.
*June 17, 2015*

**math**

the ones digit is 0,2,4,6,8 the 1000's digit is twice the one's, so must be 0,4,8 so far we have xx0xx0 or xx4xx2 or xx8xx4 now add 3 and we have 3x0xx0 7x4xx2 Now fill in the x's with whatever you want
*June 17, 2015*

**Mathematics**

r^4 = (1/4)/4 = 1/16 r = 1/2 so, the GP is 4, 2, 1, 1/2, 1/4
*June 17, 2015*

**physics**

velocity of ?
*June 17, 2015*

**algebra**

not so. Just pick a,b,c so that b^2-4ac is positive. f(x) = -x^2-10x-3 b^2 is positive whether b is positive or negative. It was all good until the last line. That's just rubbish.
*June 17, 2015*

**Calculus**

As I recall, you need Newton's law of cooling, which in this case would be T(t) = 2+23e^(-kt) where we try use a positive k. T(10) = 17, so 2+23e^(-10k) = 17 k = 0.0427 and we have T(t) = 2+23e^(-.0427t) So, after 30 minutes, T(30) = 2+23e^(-.0427*30) = 8.388 When T=4, we ...
*June 17, 2015*

**Calculus**

well of course if T(t) = 2+23e^kt T(10) will not equal T(30) You sure they're both supposed to be 17? So, what was the original problem?
*June 17, 2015*

**math help please**

company paid .80(2300)-250 Carol paid 250+.20(2300)
*June 17, 2015*

**science chemistry**

Since 1 dm^3 = 1L, .125 mol/dm^3 = .125M solution So, the 250mL amount needs .125*.250 = 0.03125 moles of KOH multiply that by the molar mass of KOH to get the number of grams.
*June 17, 2015*

**science**

Since weight varies directly with mass, Darren's weight would be half as much as on earth, given the same radius of the planet.
*June 17, 2015*

**Chemistry**

because each molecule contains 8 atoms. When figuring the mol wt, you need to use the number of molecules, not atoms.
*June 17, 2015*

**Maths**

depends on what you consider strengths. I suggest you list the various properties, and then decide what you consider to fit the bill.
*June 17, 2015*

**algebra**

try the quadratic formula: x = (-3±√(3^2+4*2*6))/4
*June 16, 2015*

**trig**

It occurred to me this might be a physics problem: sin(ωt-π)+sin(ωt+π) = -2sin(ωt)
*June 16, 2015*

**trig**

Not sure what the f is doing in there, but recall that sinA + sinB = 2sin((A+B)/2)cos((A-B)/2) I think you got too many π's floating around in there, as well. sin(x+π) = sin(x-π) = -sin(x)
*June 16, 2015*

**Math**

3*16 + 1.5*16 + 1*2 + 1 + 3*4 = 87
*June 16, 2015*

**algebra**

Sorry. That cannot be reduced. Assuming you mean (2x+1)/(4x^2+8x+5)
*June 16, 2015*

**Algebra 2**

draw the graphs as usual. Shade the area above the first. Shade the area below the second. Where the two shaded areas intersect is the solution. Note that the curve is included in the 1st, but excluded from the 2nd. http://www.wolframalpha.com/input/?i=plot++y+%3D+-x^2-8x-12+%...
*June 16, 2015*

**Algebra**

20-|7x+1| >= 6 |7x+1| <= 14 |x + 1/7| <= 2 x∊[-15/7,13/7] http://www.wolframalpha.com/input/?i=solve+20-|7x%2B1|+%3E%3D+6
*June 16, 2015*

**Algebra**

if |x-h| < n, that means that h-n < x < h+n |7-8x| < 10 | 7/8 - x| < 5/4 so, 7/8-5/4 < x < 7/8+5/4 -3/8 < x < 17/8 or, x∊(-3,8,17/8)
*June 16, 2015*

**Maths**

using the common difference of the AP, you know that x-2 = y-x Using the common ratio of the GP, you know that (x-1)/2 = y/(x-1) So, solve those two equations to get x and y.
*June 16, 2015*

**Algebra**

Read what I wrote. I guarantee that you will find the answer.
*June 16, 2015*

**Algebra**

well, you have 2m(n-8) - 7n So, if you want a common factor of n-8, you would need 56 That would give you 2m(n-8) - 7n + 56 = 2m(n-8) - 7(n-8) = (2m-7)(n-8)
*June 16, 2015*

**pre-calculus 11**

that is correct, except that you seem to be a bit fuzzy on how apostrophes are used. . .
*June 16, 2015*

**Algebra**

well, geez. You cant solve 3k+50 = 0? k = -50/3 (25 - 50/3 i)*(3+2i) = 325/3 which is a real number
*June 16, 2015*

**Algebra**

(25 + ki)*(3+2i) = 75+3ki+50i-2k = 75-2k + (3k+50)i So, you need 3k+50 = 0, since real numbers have zero imaginary part.
*June 16, 2015*

**pre-calculus 11**

Looks good to me.
*June 16, 2015*

**Algebra**

Hint: slope-intercept: y = mx+b point-slope: (y-k) = m(x-h) standard: Ax+By = C rise-run: ? never heard of it.
*June 16, 2015*

**Math**

If the area of the deck is 3 times the pool, then the total area of pool+deck is 4 times just the pool. If the width of the deck is w, you need (3+2w)(4+2w) = 4(3)(4)
*June 16, 2015*

**pre-calculus 11**

The round trip is 5400, so each half is only 2700 km. So, I get 2700/x + 2700/(95+x) = 7.6 x = 666 km/hr
*June 16, 2015*

**math**

I get the b and h for the triangular bases, but cannot figure out how the length can be both 7 and 15. Maybe you can clear that up.
*June 16, 2015*

**Maths**

If the depth is x cm, then since 1L = 1000cm^3, you have 100*140*x = 275*1000 x = 10.64 cm
*June 16, 2015*

**pre-calculus 11**

If you use some parentheses to properly specify the numerators and denominators, I think you have a typo and meant -x/(x-3) + 2x/((x+2)(x-1)) * ((x-2)(x+2))/((x-3)(x+3)) As usual, do multiplication before addition. In effect you have -x + y * z Do the y*z first, giving you -x...
*June 16, 2015*

**pre-calculus 11**

no, that would mean 8 <= t <= 16 That is an 8-hr window centered at 12:00 You want |10-t| <= 2
*June 16, 2015*

**sgmic**

I think you have it wrong: tan 3θ = tan(θ+2θ) tan 3θ = (tanθ+tan2θ)/(1-tanθtan2θ) tan3θ(1-tanθtan2θ) = tanθ+tan2θ tan3θ - tanθtan2θtan3θ = tanθ+tan2θ tan3θ - tan2θ - tan&#...
*June 16, 2015*

**math**

well, geez. Just list the even digits which sum to 12: 048 246 in whatever order you want to use them. Then sprinkle the 8's everywhere else.
*June 16, 2015*

**Math**

as you say, y = 70-2x, and the area a = xy = x(70-2x) You found the roots of that function which is where the area is zero! The vertex of a parabola is midway between the roots, at x = 17.5 So, y=35 and the maximum area is indeed 612.5
*June 16, 2015*

**Math**

If the digits, reading left to right, are abcde, then we are told b = a-2 b = c+2 So, abc are consecutive descending odd numbers. d = e+2 e = c-4 Looks like all 5 digits are in order: 97531
*June 16, 2015*

**math**

1/(2/7) = 7/2 So, there are 5/2 hours left to go.
*June 16, 2015*

**Geometry**

I must be missing something here. If AB and CD are diameters, then AD = BC, since the diameters must intersect in the center of the circle. No idea where E is.
*June 16, 2015*

**Mathematics**

see the related question below.
*June 16, 2015*

**cubic function**

That is clearly so. From the Rational Roots Theorem, you know that the only possible rational roots are ±1. So, the only way to find the roots are to graph it and try to read off the roots, or use some numerical method, such as bisection or Newton's method, or ...
*June 16, 2015*

**science**

Since you are given very little information, expect the math involved to be simple. How about you start with that most basic equation of motion: F = ma
*June 16, 2015*

**trig**

The 6 feet at the top is just noise, placed there to see whether you know how to subtract. The wire is attached 465 feet from the ground. So, you have a right triangle with an angle of 23.1° opposite the pole. (assuming the pole is vertical) Checking your basic trig ...
*June 16, 2015*

**Math**

Assuming you meant 131/10 = 20/x that would give you 131x = 20*10 x = 1.5 What can that mean? The ratios do not seem intuitive to me. I would have reasoned this way: Of the sample caught, 10/20 were tagged. We can expect that the same fraction of the total population was ...
*June 15, 2015*

**Physics**

Draw the two vectors. The resultant speed is the hypotenuse of the triangle. That is, √(2.4^2 + 1.7^2) = 2.94 m/s The direction is arctan(1.7/2.4) = E35.3°S
*June 15, 2015*

**Differential equation**

sorry - had to run off - also had a typo above d((x+4)^5 y) = 16(x+4)^3 (x+4)^5 y = c + 4(x+4)^4 y = c/(x+4)^5 + 4/(x+4) Now you can solve the initial value problem.
*June 15, 2015*

**Differential equation**

we have (x+4)^2y′+5(x+4)y=16 y' + 5/(x+4) y = 16/(x+4)^2 The integrating factor is e^(∫5/(x+4) dx) = (x+4)^5 So, multiplying through by that we have (x+4)^5 y' + 5(x+4)^4 y = 16(x+4)^3 d((x+4)^5 y = 16(x+4)^3 x+4)^5 y = 4(x+4)^3 + C ...
*June 15, 2015*

**Differential equation**

since e^lnu = u and (e^a)^b = e^(ab) e^(5ln(x+4)) = (e^ln(x+4))^5 = (x+4)^5 That help?
*June 15, 2015*

**Maths**

w(w+3)*16 = 364 now just solve for w.
*June 15, 2015*

**algebra**

the two functions are 40+8m 25+12.5m Now go for it...
*June 15, 2015*

**math**

Assuming you meant 16 passed math, Draw your Venn diagram and start filling in the missing pieces. 3 passed all three subjects 7 passed E and M 1 passed M only So, 33 passed something. I expect you can take it from there.
*June 15, 2015*

**MATH**

Hmm. I get a negative value for q. Is there maybe a typo?
*June 15, 2015*

**math - eh?**

beats me. you want to explain in words what you are trying to solve? Like, how long does it take to administer 1000ml at 15 drops per hour, or something like that? Your units are all mixed up. On the left, you have ml*gtt*hr On the right you have ml*gtt*hr*min I think you need...
*June 15, 2015*

**math 4**

since the events are independent, p = (1/2)(1/2)(1/2)
*June 15, 2015*

**math**

gee, does not the name of the function tell you how to fill in the blank?
*June 15, 2015*

**Math**

Looks like about 8% to me
*June 15, 2015*

**Math-NPV**

You want NPV, using NPV(.11,11) = -110000 + sum(t=1 to 11) 17000/(1+.11)^t = -110000 + 105510.76 = -4489.24 NPV(.17,11) = -110000 + 82219.03 = -27780.97 the IRR is r where sum(t=1 to 11) 17000/(1+r) = 110000 r = 10.08%
*June 15, 2015*

**algebra**

so, did you get out your graph paper and plot the points? They are (0,3), (-9,0), and (-3,0) The vertex is at (-6,-3) You know the graph will be V-shaped. Since you know that there will be a minimum at x = -6, the V opens upward. You know that the point of the V is at x = -6. ...
*June 15, 2015*

**calculus**

s(t) = ∫ v(t) dt = ∫ 4-t^2 dt = 4t - 1/3 t^3 + C Since s(0) = 0, C=0, and s(t) = 4t - 1/3 t^3
*June 15, 2015*

**calculus**

h(t) = 64t-16t^2 so, at max height, dh/dt=0. So, find t for that.
*June 15, 2015*

**algebra**

well, why not just plug in the values for x? f(3)-f(2) = 3|3-1| - 3|2-1| = 3*2-3*1 = 3 Now divide that by 3.
*June 15, 2015*