Срочном упростите выражение

(√6 + √3) * √12 - 2√6*√3 =
= √(6*12) + √(3*12) - √ (4*6*3) =
= √(6² *2) + √6² - √(6² *2) =
= 6√2 + 6 - 6√2 = 6

$( \frac{6}{y^2-9} + \frac{1}{3-y} )* \frac{y^2+6y +9}{5} = \\ \\ = (\frac{6}{y^2-3^2} + \frac{1}{- (y-3)} ) * \frac{y^2+2*y*3+ 3^2}{5} = \\ \\ = (\frac{6}{(y-3)(y+3)} - \frac{1}{y-3} ) * \frac{(y+3)^2}{5} = \\ \\ = \frac{6-1*(y+3)}{(y-3)(y+3)} * \frac{(y+3)^2}{5} = \\ \\ = \frac{6-y-3}{(y-3)(y+3)} * \frac{(y+3)^2}{5} = \\ \\ = \frac{- (y-3)*(y+3)^2}{(y-3)(y+3)*5} = \\ \\ = \frac{-1*(y+3)}{5} = - \frac{y+3}{5} = \\ \\ = -\frac{1}{5} *(y+3) = -0.2(y+3)= \\ \\ =- 0.2y -0.6$