Poll of the Day > Ok, I am failing at this math question and it is driving me insane

(+) Yeah! (+)

Solve for A:

S={A-A*R^N}/1-R

1) Multiply both sides by (1-R) ==> S(1-R) = A-A*R^N
2) Divide both sides by R^N ==> [S(1-R)]/R^N = A-A
3) Distribute...

I get (S-Sr)/R^N=A-A but apparently the answer is A=(S-Sr)/(1-R^N)

where'd that 1 come from/what number concept am I missing D:
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It's 5/7

The perfect score
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You cant divide by r^n

After step 1 it is a-ar^n

So if you divide by r^n it is (a/(r^n))-a
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JOExHIGASHI posted...

You cant divide by r^n

After step 1 it is a-ar^n

So if you divide by r^n it is (a/(r^n))-a

Forgot to divide the other A by R^...

JOExHIGASHI posted...

You cant divide by r^n

the fuck then how do you get the answer?!
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After step 1:

a-ar ^n which can be rewritten as a(1-r^n)

a (1-r^n)=s-sr

Divide both sides by 1-r^n

Now you have the answer
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JOExHIGASHI posted...

a-ar ^n which can be rewritten as a(1-r^n)

Oh, that makes since, didn't think of even distributing that way (or reverse distributing, whatever)

Really appreciate this!
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It seems you got it. You had made a mistake when you divided by R^N because you need to divide both A terms by it.

So on step 2 you should have:
[S(1-R)]/R^N = A/(R^N) - A.
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