On considère l'expression suivante : E(x) = (x-5)(2x+3)-(2x+3)² Développer E Résoudre l'équation : E(x) = 0 Svp !

bonsoir

E(x) = (x-5)(2x+3)-(2x+3)²
e = 2x²+3x-10x-15 -(4x²+12x+9)
e = 2x²-7x-15-4x²-12x-9
e = -2x²-19x-24

E(x) = (x-5)(2x+3)-(2x+3)²  =0
(2x+3)(x-5-2x-3) =0
(2x+3)(-x-8) =0

2x+3 =0                      -x-8 =0
2x = -3                           -x =8
x = -3/2                           x = -8