Question

a+7 7
___ - ___
49-a² 7a-a²

Answer 1

Ответ:

$frac{a + 7}{(7 - a)(7 + a)} - frac{7}{a(7 - a)} = \ = frac{ {a}^{2} + 7a - 49 - 7a }{a(7 - a)(7 + a)} = frac{ {a}^{2}- 49 }{a(7 - a)(7 + a)}$= -а