Developper et reduire :( x-6)² - (x-4)(x-9)

(x-6)² - (x-4)(x-9)
= (x² - 2(6)(x) + 36) - ( x² -9x -4x + 36)
= x² -12x +36 -x² +9x +4x -36
= x

(x-6)²-(x-4)(x-9)
(x-6)(x-6)[x-4-x-9]
x²-6x+36 -x-4-9
x²+42-9