Rewrite the equation so that the x term is on the left:
9 - 3x = -18
Move the number to the right and change the sign:
-3x = -18 - 9
-3x = -27
Change the sign of both terms:
3x = 27
Move the 3 to the right and change the sign:
x = 27 ÷ 3
x = 9 is your answer.
