Réponse :
Utilison la formule (a+b)(a-b) = a²-b²
A = (5x-2)(5x+2)+5(4x+3)
= (25x²-4)+(20x+15)
= 25x²+20x+11
P = (5x-1)(5x+1) - (3x-4)
= 25x²-1-3x+4
= 25x²-3x+3
B = (2x+8)2+(4x-7)(3x-8)
= 4x+16+(12x²-32x-21x+56)
= 12x²-49x+72
C = (7y+1)(7-4y) - (2y+9)(2y-9)
= (49y-28y²+7-4y) - (4y²-81)
= (-28y²+45y+7) - (4y²-81)
= -28y²-4y²+45y+7+81
= -32y²+45y+88
Explications étape par étape :
