Exercice n°4 :
A = (2x + 7) (42 - 2) +7(6x-9)

B=2(8x+2)+(4x+5)(7x-2)

C= (2x - 9) (4x - 5) - 7(3x - 10)

D= (8y + 5)(2y + 3) + (6y-10) (y - 1)

E = (x - 7) (3x + 10) + (9x - 1)(x-6)​