Hello there!
In order to solve that equation, you would need to distribute the 3 inside the parenthesis.
-10x + 3(4x - 2) = 6
-10x + 12x - 6 = 6
Then you would need to keep the variable in the left and everything else to the right - in other words, solving for x.
-10x + 12x - 6 = 6
2x = 12
x = 6
Your answer would be 6.