Réponse :
1) A = 3x(x-5)-(x²-7x-2)
A = 3x²-15x-x²+7x+2
A = 2x²-8x+2
B = (1-2x)(1+2x)
B = 1²+2x-2x-4x²
B = 1-4x² = -4x²+1
ou B =(a-b)(a+b) = a²-b²=1-4x²
C = (3x-2)²+3x(1-x)
C = 9x²-12x+4+3x-3x²
C = 6x²-9x+4
2 :
a(x) = 3x^3-12x²+3x
a(x) = 3x(x²-4x+1)
b(x) = (x-5)(2x+3)+2x-10
b(x) = (x-5)(2x+3)+2(x-5)
b(x) =(x-5)(2x+3+2)
b(x) = (x-5)(2x+5)
c(x) = 16x²-24x+9 = a²-2ab+b²=(a-b)² = (4x-3)²
Explications étape par étape :
