7/ C'est la A
E= (3x+5) (x-2) -(x-2) (x+17)
E= 3x×x+3x×(-2) +5×x+5×(-2) -x×x-x×17+2×x+2×17
E= 3x²-6x+5x-10-x²-17x+2x+34
E= 2x²-16x+24
8/C'est la C
E= (3x+5) (x-2) -(x-2) (x+17)
E= (x-2) [ (3x+5) -(x+17)
E= (x-2) [ 3x+5-x-17)]
E= (x-2) [ 2x-12]
9/ C'est la ?
F= (2x-1)²-(3x+5) (2x-1)
F= (2x)²-2×2x×1+1²-3x×2x-3x× (-1) +5×2x+5×(-1)
F= 4x²-4x+1-6x²+3x+10x-5
F= -2x²+9x-4
10/C'est la C
F= (2x-1)²-(3x+5) (2x-1)
F= (2x-1) (2x-1) - (3x+5) (2x-1)
F= (2x-1) [ (2x-1) -(3x+5) ]
F= (2x-1) [ 2x-1-3x-5]
F=(2x-1) [ -x-6]
11/C'est la B
25x²-16
(5x)²-4²
(5x+4) (5x-4)
12/ C'est la B
16x²-8x+1
(4x)²-2×4x×1+1²
(4x-1)²
