in equations we always want to do the same thing to both sides so the equation stays equal
in an equation with one unknown (x) we try to get the unknown on one side
so -(x-10)
this means that you multiply everything in the equation by -1 or in other words you make everything in the parenthasees the opposite sign of what it is so
6x+3x-x+10=20x
add like terms
8x+10=20x
subtract 8x from boths sides
10=12x
divide both sides by 12
10/12=x=5/6
