Упростите: 2 (y-6) - (y-9)(y+4)

Question

Упростите:
2
(y-6) - (y-9)(y+4)

Answer 1

(y-6)² - (y-9)(y+4) = y²-12y+36-(y²+4y-9y-36) =  y²-12y+36-y²+5y+36 =72 -7y