Answer:
x = 20
Explanation:
you can notice that those two are identical, so it's a basic equation
3x + 50 = 6x - 10
and now we can solve it by moving x'es to one side and number to the other (remembering that when you do that you need to change the sign, so if there is "-" then change to "+"):
50 = 6x - 10 - 3x
50 = 3x - 10
50 + 10 = 3x
60 = 3x
20 = x