Sagot :
A(x) = x²-1+(2x-1)(x+1)
= x² - 1 + 2x² + x - 1
= 3x² + x - 2
A(x) = x²-1+(2x-1)(x+1)
= (x-1)(x+1)+(2x-1)(x+1)
= (x+1)(x-1+2x-1)
= (x+1)(3x-2)
A = x²-1 + (2x²+2x-x-1)
A = x²-1+2x²+2x-x-1
A = 3x² +x -2
factorisation
A = (x+1)(x- 1)+(2x-1)
= (x+1)(x-1+2x-1)
= (x+1)(3x-2)