Помогите решить пример.

Решите задачу:

$1)()= \frac{5m}{m+3}- \frac{14m}{(m+3) ^{2} } = \frac{5m(m+3)-14m}{(m+3) ^{2} } = \frac{5m ^{2}+15m-14m }{(m(5m+1) ^{2} }$

$2) \frac{m(5m+1) }{(m+3) ^{2} } : \frac{5m+1}{m ^{2}-9 } =$

$= \frac{m(5m+1)(m-3)(m+3)}{(m+3) ^{2}(5m+1) } = \frac{m(m-3)}{m+3}$

$3) \frac{m(m-3)}{m+3} + \frac{3m-9}{m+3}= \frac{m(m-3)+3(m-3)}{m+3}= \frac{(m-3)(m+3)}{m+3}=m-3$