Division Property of Equality.
Always use opposite operation with side that contains variable.
Isolate variable.
Divide 4 by 4 to get it by itself.
Now do the same to other side.
[latex]12\div4=3\\x=3[/latex]

BettieZumbrunnen

12 = 4 x / / / Divide each side by 4. / / / 3 = x .