Sagot :
Réponse :
Explications étape par étape
Bjr,
A=(x+7) (3-2x) + (5x-2) (4x+1)
(x+7) (3-2x) = 3x+2x² +21 -14x = 2x² -11x +21
(5x-2) (4x+1) = 20x² +5x -8x -2 = 20x² -3x -2
2x² -11x +21 + 20x² -3x -2 = 22x² - 14x +19
B=(5x-2) (5x-8) - (3x-5) (x+7)
(5x-2) (5x-8) = 25x² -40x -10x +40 = 25x² -50x +40
(3x-5) (x+7) = 3x² +21x -5x -35 = 3x² +16x-35
25x² -50x +40 -[ 3x² +16x-35 ]=
25x² -50x +40 - 3x² -16x+35 =22x² -66x +75
C=(2x+3) (5x-8) - (2x-4) (5x-1)
(2x+3) (5x-8) = 10x² -16x +15x -24 = 10x² -x -24
(2x-4) (5x-1) = 10x² -2x -20x+4 = 10x² -22x +4
10x² -x -24 -[ 10x² -22x +4]=
10x² -x -24 - 10x² +22x -4= 21x -28
☺
