Sagot :
(E1)10x-21-10x=7x+9-10x| -21=-3x+9|-21-9=-3x+9-9|-30=3x|-30/3=-3x/3| x=-10
10x-21 = 7x+9
10x-7x = 9+21
3x = 30
x = 10
24x-15 -6x+10 = 4x+4-2x
= 24x-6x-4x+2x = 4+15-10
16x = 9
x = 9/16
14x-21-4x-10 = 10x-30-1
14x-4x-10x = -30-1+21+10
8x = 0
x = 0
12x+21-6x+3 = 6x+7
12x-6x-6x = 7-21-3
0x = -17
4x-5x/7+1 = 2/3
21x/21-15x/21 = 14/21
21x-15x = 14
6x =14
x = 14/6 = 7/3
dans le E3, il manque une parenthèse ou un signe