Bonsoir,
1) A(x) = (2x - 1)(x + 4) + (2x - 1)
A(x) = 2x*x + 2x*4 - x - 4 + 2x - 1
A(x) = 2x² + 8x - x - 4 + 2x - 1
A(x) = 2x² + 9x - 5
2) A(x) = (2x - 1)(x + 4) + (2x - 1)
A(x) = (2x - 1)(x + 4) + (2x - 1) * 1 je peux factoriser par (2x-1)
A(x) = (2x - 1) * (x + 4 + 1)
A(x) = (2x-1) ( x + 5)
Bonne soirée
