(1/2)(x + 6) = 25
You have to do the sum first so the 1/2 has to be outside of the parenthesis.
Distribute the 1/2 through the parenthesis.
1/2x + 3 = 25
subtract 3 from both sides
1/2x = 22
multiply 2 on both sides to clear the fraction
x = 44
CHECK
(1/2)(44 + 6)
(1/2)(50)
25