is it 1/2x - 5 or 1/(2x - 5)?

you can check by pluging in your answer into the original equation and see if everything checks out. you got x = 30, so

1/3(30) should be equal to 1/2(30) - 5

not true, your answer would be wrong either way, whether it is 1/2x - 5 or 1/(2x - 5)