1) a) (x+3)² - 4 = x² + 6x + 9 - 4 = x² + 6x + 5
b) x² + 6x + 5 = (x+3 - 2)(x+3 + 2) = (x+1)(x+5)
2) a) A(x) = (x+1)(x+5 - (4x+7)) = (x+1)(-3x -2)
b) x = -1 ou x = -2/3
c) positive sur [-1 ; -2/3] et negative ailleurs
d) solution ]-oo ; -1[U]-2/3 ; +oo[
