2+x=8-x
add x to each side to get all the x's on one side
2+x+x = 8-x+x
2 + 2x = 8
now subtract 2 from each side to get all the numbers on the other side
2 + 2x -2 = 8-2
2x = 6
divide by 2 on each side to get x alone
2x/2 = 6/2
x=3
Answer: x=3
