Bonjour j'ai besoin d'aide svp. ​

a) M = 11x+7-5x+3+x-21
M = 7x-11

b) N = 3(5x-4)+4x+7
N = 15x-12+4x+7
N = 19x-5

P = (2x+3)(3x-5)
P = 6x²-10x+9x-15
P = 6x²-x-15

c) x=3
N = 19*3-5 = 52

d) x=-4
P = 6*(-4)²-(-4)-15
P = 6*16+4-15
P = 72-11
P = 61