Question

Только под буквой "а)

Answer 1

Ответ:

$\frac{a-1}{a+3}$

Объяснение:

$(a-\frac{a^{2}+9 }{a+3} )(\frac{1}{3}+\frac{2}{a-3} )=\\(\frac{a^{2} + 3a-a^{2}-9 }{a+3})(\frac{a-3+2}{3(a-3)} ) =\\(\frac{3a-9}{a+3} )(\frac{a-1}{3(a-3)} )=\frac{3(a-3)(a-1)}{(a+3)3(a-3)} =\\\frac{a-1}{a+3}$