Solving an equation with a variable on both sides of the equation require a few more steps. However, it is not complicated at all once you understand how to solve two-step equations.
Example #1
Solve 9x - 12 = 5x + 8
9x - 12 = 5x + 8
Subtract 5x from each side of the equation
9x - 5x - 12 = 5x - 5x + 8
4x - 12 = 0 + 8
4x - 12 = 8
Add 12 to each side of the equation
4x - 12 + 12 = 8 + 12
4x + 0 = 20
4x = 20
Divide each side by 4
4x/4 = 20/4
x = 5
Check
9x - 12 = 5x + 8
9(5) - 12 = 5(5) + 8
45 - 12 = 25 + 8
33 = 33
Example #2
Solve 3y + 11 = 31 - 7y
3y + 11 = 31 - 7y
Add 7y to each side of the equation
3y + 7y + 11 = 31 - 7y + 7y
10y + 11 = 31 - 0
10y + 11 = 31
Subtract 11 from each side of the equation
10y + 11 - 11 = 31 - 11
10y + 0 = 20
10y = 20
Divide each side by 10
10y/10 = 20/10
y = 2
Check
3y + 11 = 31 - 7y
3(2) + 11 = 31 - 7(2)
6 + 11 = 31 - 14
17 = 17