\frac{6}{x^{2}+3 x-28}+\frac{2}{x+7} \frac{2(x+4)}{(x+7)(x-4)} \frac{8}{(x+7)(x-4)} \frac{2(x-1)}{(x+7)(x-4)} \frac{2(x+7)}{x-4}