Question

найдите значение выражения 45а/25а2-16б2-9/5а+4б

Answer 1

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