12x - (4x+ 10) = 54

Count the x's = 12 + (-4)
Count the numbers: -10 + -54; move the 54 to the other side

8x-64 = 0; take it from there.

Moving stuff around is just an exercise in futility and stuff gets misplaced.

I do it this way, just in case you can more understand the way I do...



Expand the brackets. To do this, multiply the negative sign with each of the terms in brackets:



Now, group the terms in x and without x on one side, say the ones with x on the left side and the ones with no x on the right side. To do this, add 10 to both sides:





Now, work this out:





Can you continue now?