СРОЧНО!!!!!УМОЛЯЯЯЯЁ

$( \frac{b}{b^2-36}- \frac{b-6}{b^2+6b} ): \frac{2b-6}{b^2+6b} - \frac{b}{b-6} =-1 \\ \\ 1) \frac{b}{b^2-36}- \frac{b-6}{b^2+6b} = \frac{b}{(b-6)(b+6)} - \frac{b-6}{b(b+6)} = \frac{b^2}{b(b-6)(b+6)} - \\ \\ - \frac{(b-6)(b-6)}{b(b-6)(b+6)} = \frac{b^2-(b-6) ^{2} }{b(b-6)(b+6)} = \frac{b^2-b^2-36+12b}{b(b-6)(b+6)} = \frac{12b-36}{b(b-6)(b+6)} = \\ \\ = \frac{12(b-3)}{b(b-6)(b+6)} \\ \\2) \frac{12(b-3)*b(b+6)}{b(b-6)(b+6)*2(b-3)} = \frac{6b}{b(b-6)} = \frac{6}{b-6} \\ \\$
$3) \frac{6}{b-6} - \frac{b}{b-6} = \frac{6-b}{b-6} =- \frac{b-6}{b-6} =-1$