# Reversing an equation

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I'm not real good at math so I'm wondering if someone here could help me.

How would I reverse this?:

a = (last a * b / constant) + constant;

Thanks

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Reverse it for what? last, or b?

You just go:

[s]a = (last a * b / constant) + constant
a - constant = last * a * b / constant
(a - constant) * constant = last * a * b
((a - constant) * constant) / a = last * b

At this point you either divide both sides by last or b, depending on what you wish to solve for.[/s]

*scratch that I misread* Edited by Bacterius

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Sorry, I wanted to solve for last a.

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a = (last a * b / constant) + constant;

a - constant = last a * b / constant

(a - constant) * constant = last a * b

last a = ((a - constant) * constant) / b

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Here's a pretty good tutorial on how to get to those solutions:

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No joke... you should snag an Algebra for Dummies book. It's such a very useful thing to know! There are also AP study guides for algebra, which may be a little more in-depth. I usually bought my math books at the used book store. $5 for a$30 book. That way I get to have multiple pre-owned references for the price of one new reference! Cheap, effective.