Bonsoir,
1)
3x= 7
x= 7/3
2)
6-4 = x
x= 2
3)
3x+21 = 9
3x= 9-21
3x = -12
x= -12/3 = -4
4)
x=8
3x-x =-1 -7
2x= -8
x = -8/4 = -2
6-14 = x+x
-8 = 2x
x= -8/2 = -4
3x+21 = 4x+9
21-9 = 4x-3x
12 = x
2x -8 = 7x-2
-8+2 = 7x-2x
-6 = 5x
x= -6/5
