If 3x+9 = (10+x) then what does x equal?

3x + 9 = 10 + x

2x + 9 = 10

2x = 1

x = 1/2

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

3x+9=10+x

minus x both sides

3x-x+9=10+x-x

2x+9=10+0

2x+9=10

minus 9 both sides

2x+9-9=10-9

2x+0=1

2x=1

divide both sides by 2

x=1/2