x+6+3x=30
x+3x+6= 30 ( combine like terms)
4x+6= 30
move 6 to the other side
sign changes from +6 to -6
4x+6-6= 30-6
4x= 30-6
4x= 24
divide both sides by 4 to get x by itself
4x/4= 24/4
answer:
x= 6
