Your first step is to add 24 to both sides so you can get rid of the -24 without making the equation uneven, so that you get:
6x=54
Then, to isolate x, you divide both sides by 6, for the same reasoning I explained earlier. You will then have your answer, in which x is equal to 9.
To check, substitute 9 into the equation:
6(9)-24=30
54-24=30
30=30
