The equation is 3x - 8 = 0.
So, 5 is a solution if we replace x by 5 and we get 0 on the left side of the equation.
Then, replacing x by 5, we get:
3x - 8 = 0
3*5 - 8 = 0
15 - 8 = 0
7 = 0
Since 7 is different from 0, 5 is not a solution.
Answer: 5 is not a solution