x = 30
The distributive property says that we need to multiply what's in the brackets by 1/2 (so 1/2*x and 1/2*6) to get the equation 1/2x + 3 = 18.
Then we need to subtract our constant, 3, from boths sides to get 1/2x = 15.
Multiply both sides by two to isolate x and you get x = 30.
Hope this helps! :)