A = -(4x+1)² + 16
= 16 - (4x+1)²
= 4² - (4x+1)²
= [4+(4x+1)][4-(4x+1)]
= (4x+5)(-4x+3)
B= 64x² + 160x + 100
= (8x)² + 2*8x*10 + 10²
= (8x+10)²
Ne serait-ce pas plutôt : C = (-3x + 9)+(-3x+9)×(-2x+8) ?
D = -49x²+81
= -(7x)² + 9²
= 9² - 7x²
= (9-7x)(9+7x)
E = (8x-1)*(8x-6)+8x-1
= (8x-1)*(8x-6) + (8x-1)*1
= (8x-1)[(8x-6)+1)]
= (8x-1)(8x-5)