Factoriser : C = (x - 5)(x + 6) - (x - 5)(2x - 3) D = x^2 - 81 + (x + 9)(5 - x) Merci de l'aide :)

C= (x-5) (x+6-2x-3)
= (x-5) ( -x+3)

bonsoir

C = ( x -5) ( x +6 - 2 x +3)
C = ( x -5) ( - x + 9)

D = x² - 81 + ( x +9) ( 5 -x )
D = ( x -9)(x +9) + (x +9) (5 -x )
D = ( x +9) ( x -9 + 5 -x)
D = ( x +9) ( - 4)