# Change subject of this equation

How do I change the subject of the equation below to $b$?

$$a = \frac{k}{2b + 4c}$$

I'm getting nowhere with this one.

• Welcome to the Math StackExchange. What have you tried? – Paul Sundheim Oct 1 '14 at 20:40

rearrange in a few steps: $$2ab+4ac=k$$ $$2ab=k-4ac$$ $$b=\frac{k-4ac}{2a}$$