Answer
$-\frac{3}{2 -b} $
Work Step by Step
Since we already have common denominators, we can add and simplify the numerators, and as needed, combine like terms:
$\frac{1}{2 - b} - \frac{4}{2 - b} =\frac{1 - 4}{2 - b}
= \frac{-3}{2 -b} =-\frac{3}{2 -b} $
