bonsoir
A = ( 4 x + 2 ) ( 3 x - 5 )
remplacer x par 2
A = ( 8 + 2 ) ( 6 - 5 ) = 10 x 1 = 10 il est où le problème ?
B = 10 - 4 - 2 ( 3 - 2 ) = 10 - 4 - 2 x 1 = 6 - 2 = 4
C = 3 - 4 ( 8 - 5 ) = 3 - 4 x 3 = 3 - 12 = - 9
A = 12 x² - 20 x + 6 x - 10
= 12 x² - 14 x - 10
= 12 * 2² - 14 *2 - 10 = 48 - 28 - 10 = 10
B = 5 x - 4 - 6 + 2 x
= 7 x - 10 = 14 - 10 = 4
C = 3 - 8 x² + 10 x = 3 - 8 *4 +/10 * 2 = 3 - 32 + 20 = - 9