1. (les x sont des fois)
(3 x(-2)+2) 2-(3 x(-2)+2) (-2 +1)
= (-6+2) x 2-(-6+2) x (-1)
= -4 x 2 -(-4) x (-1)
= -4 x 2 + 4 x (-1)
= -4 x 2 -4 x 1
= 4 x (-1) x (2+1)
= 4 x (-1) x 3
= -12
2. (3x+2)2-(3x+2)(x+1)
= (3x +2) (2-(x+1))
= (3x+2) (2-x-1)
= (3x+2) ( 1-x)
= 3x -3x^2 + 2-2x
= x -3x^2 + 2
= -3x^2 +x +2
(x^2 se lit x au carré)
3. (3x+2)2-(3x+2)(x+1)
= 2(3x+2)-(3x+2)(x+1)
= (3x+2) (2-(x+1))
= (3x+2) (2-x-1)
= (3x+2)(1-x)
