First, we should combine the similar terms. If you look closely at the right hand side of the equation, you'll find 5x and -3x. You can combine these two to get 2x (because 5x - 3x = 2x).
Now, your equation becomes 24 = 2x + 6 instead of 24 = 5x + 6 - 3x.
We should now subtract 6 from both sides of the equation to isolate the 2x:
24 - 6 = 2x
18 = 2x
Now, we just need to divide both sides of the equation by 2 to get the x by itself and solve the problem to work out x:
18 รท 2 = x
9 = x
And your solution for x has been worked out. The answer is x = 9 :)