Let's write an equation first:
x divided by 4 can be represented as x/4
So, x/4 = 12
Now to isolate x, multiply by 4 to cancel the four out. If you do this to one side, you have to do it to the other.
(x/4)4 = 12(4)
so that leaves us with x = 48
In order to get 12 as an answer, x would have to represent 48.
Hope this helps!
