Simplifying a fraction of polynomials

Question

This is a really simple question. All I want to know is how it goes from that first line of the equation to the second line, what is it they're doing. I'm just missing something, can someone explain. $$ \begin{split} H(z) &= \frac{0.3249(z+1)}{(z-1)+0.3249z+0.3249}\\ H(z) &= \frac{0.3249(z+1)}{1.3249z-0.6751} \end{split} $$

Answer 1

Note that the denominator can be simplified: $$ (z-1) + 0.3249z + 0.3249 = (z + 0.3249z) + (0.3249-1) = 1.3249z - 0.6751. $$