Répondre :
A= 7(2x-1)(5x+3) - 5(14x-1)(x-2)
=7(10x²+6x-5x-3)-5(14x²-28x-x+2)
=7(10x²+x-3)-5(14x²-29x+2)
=70x²+7x-21-70x²+145x-10
=152x-31
B= (x+y-1)²- (x+y+2)² est de la forme a²-b²=(a+b)(a-b)
=(x+y-1-x-y-2)(x+y-1+x+y+2)
=(-3)(2x+2y+1)
=-6x-6y-3