A= (x+3)(5-3x)
= (x-3) (-3x + 5)
= x (-3x + 5) + 3 (-3x + 5)
= -3x² + 5x + 3 (-3x + 5)
= -3x² + 5x - 9 + 15
= -3x² -4x + 5
essaie de faire le B seul(e)
C= (3x-6)
= 3(x-2)
D= (4-2x)(4+2x)
= (-2x+4) (4+2x)
= (-2x+4) (2x+4)
= -2x (2x+4) +4 (2x+4)
= -4x²-8x+4(2x+4)
= -4x² -8x +8x +16
= -4x² +16
E= 2x² +(x-4) (3-x)
= 2x² + (x-4) (-x+3)
= 2x² + x(-x+3)-4(-x+3)
= 2x²-1x²+3x-4(-x+3)
= 2x²-1x²+3x+4x-12
= 2x²-1x²+7x-12
= 1x²+7x-12
= x²+7x-12
essaie de faire le F seul(e)
