bonjour
1)
A(x) = (2x + 1)(1 - 3x) - 2(2x + 1)
A(x) = 2x * 1 - 2x * 3x +1 - 3 x - 2*2x - 2
A (x) = 2x -6x² + 1 - 3x - 4x - 2
= -5x - 6x² - 1
2)
A (x) = (2x + 1)(1 - 3x) - 2(2x + 1)
= (2x+1) ( 1-3x -2)
= (2x+1) ( -3x - 1 )
3)
on a d'après la question 1 que A(x) = -5x -6x² - 1
on calcule A(-1) = -5*-1 - 6 * (-1)² - 1 = 5 - 6 - 1 = - 2
bonne continuation
