4x-63=9x+57
We want to get x on one side, so we can either remove the x on the left side or the x on the right. To cancel out the x on the left, we need to subtract 4x from both sides, or alternatively to cancel out the x on the left we subtract 9x from both sides. For ease I subtracted 4x from both sides.
4x-63quadcolor(red)(-quad4x)=9x+57quadcolor(red)(-quad4x)
-63=5x+57
Now we want to get x by itself, so we start by subtracting 57 from both sides:
-63quadcolor(red)(-quad57)=5x+57quadcolor(red)(-quad57)
-120=5x
Divide both sides by 5 to get x completely by itself:
-120/color(red)5=(5x)/color(red)5
-24=x
x=-24