a) $$ \frac{-6x-3}{(2x-3)(2x+3)} - \frac{2}{3-2x} = \frac{-3(2x+1)}{(2x-3)(2x+3)} + \frac{2}{2x-3} = \frac{-3(2x+1) + 2(2x+3)}{(2x-3)(2x+3)} = \frac{-6x-3 + 4x + 6}{(2x-3)(2x+3)} = \frac{-2x+3}{(2x-3)(2x+3)} = \frac{-(2x-3)}{(2x-3)(2x+3)} = \frac{-1}{(2x+3)} $$
Ответ: $$ \frac{-1}{2x+3} $$