Rearranging a fixed point equation

Hi, sorry if this is a silly/simple question! But i've been banging my head against it for a while. There's an example of a fixed point equation in my course book that gives $\displaystyle \frac{-1}{8}x^2+\frac{5}{8}x+\frac{7}{2}=x$

But then rearranges to give $\displaystyle x^2+3x-28=0$

I can see they're dividing through by the 'a' coefficient for the quadratic, but I don't understand the operation involved in turning the 'b' coefficient from 5/8 divide by 1/8, which gives me 5, into the 3 when the RHS (which is 'x' over 1/8) is transposed.

Any help/hints greatly appreciated! Thanks.