Question

45a/25a^2-16b^2-9/5a+4b при a=5 b=5

Answer 1

Ответ:

0,8

Объяснение:

$\frac{45a}{25a^2-16b^2}-\frac{9}{5a+4b}=\frac{45a}{(5a+4b)(5a-4b)}-\frac{9(5a-4b)}{(5a+4b)(5a-4b)}=\\\\=\frac{45a-45a+36b}{(5a+4b)(5a-4b)}=\frac{36b}{25a^2-16b^2}\\\\a=5,\; \; b=5\\\\\frac{36*5}{25*5^2-16*5^2}=\frac{36*5}{5^2(25-16)}=\frac{36}{5*9}=\frac{4}{5}=0,8$