Bonsoir,
C = (3x + 2)(4x + 5) - (x-3)(2x - 5)
= 12x² +15x +8x +10 -( 2x² -5x -6x +15)
= 12x² +15x +8x +10 - 2x² +5x +6x -15
= 10x² +34x -5
D = -2(3x + 1)² - (2x - 1)(3-x)
= -2( 9x² +6x +1) - ( 6x -2x² -3 +x)
= -18x² -12x -2 -6x +2x²+3 -x
= -16x² -19x +1
Excuse- moi pour l'erreur, j'ai corrigé!
E = (2+3x) (4x-1)-(3x - 1)²
= 8x -2 +12x² -3x -( 9x² -6x +1)
=8x -2 +12x² -3x - 9x² +6x -1
= 3x² +11x -3
