bonjour
B = 21 x - 35 - 6 x² + 10 x
B = - 6 x² + 31 x - 35
Bonsoir,
double distributivité
7*3x = 21x
7*-5 = -35
-2x*3x = -6x²
-2x* -5 = 10x
=>
-6x² +21x +10x -35
-6x² +31x -35