Question

What's the answer to: ‎X + 9 = 18 - 2x?

Answer 1

Remember you can do anything to an equation as long as you do it to both sides

x+9=18-2x
add 2x to both sides
2x+x+9=18+2x-2x
3x+9=18+0
3x+9=18
minus 9 both sides
3x+9-9=18-9
3x+0=9
3x=9
divide both sides by 3
(3x)/3=9/3
(3/3)x=3
1x=3
x=3