Factoriser
A=(4x²-1)+(2x-1)(x+2)
A= (2x-1)(2x+1) + (2x-1)(x+2)
A= (2x-1)(2x+1+x+2)
A= (2x-1)(3x+3)
B=x²-4x+(x+1)(4x-16)
B=x²-4x+4x²+4x-16x-16
B= 5x²-16x-16
Δ= 576
Δ > 0 , l'équation admet 2 solutions x1 et x2
x1 = -4/5
x2= 4
Factorisation : 5(x+4/5)(x-4) ⇒α(x-x1)(x-x2)
C=(2x+4)(x-3)+(4x+8)(x-1)-5(x+2)
C= 2(x+2)(x-3)+4(x+2)(x-1)-5(x+2)
C= (x+2)[2(x-3)+4(x-1)-5]
C= (x+2)(2x-6+4x-4-5)
C= (x+2)(6x-15)