we simplify the equation to the form, which is simple to understand
7x-(3x+2x)-x=0
Simplifying terms in parentheses
7x-(+5x)-x=0
Remove unnecessary parentheses
7x-5x-x=0
We move all terms containing x to the left and all other terms to the right.
+7x-5x-1x=0
We simplify left and right side of the equation.
+1x=0
We divide each sides of the equation by 1 to get x. x=0