Ok first you subtract 8 from both sides.
The eights cancel out so left with x=1, becuase positive 8 subtract negative 8, (draw a number line this will help alot) gives you zero and 9 minus 8 equals 1, so then drop down what you have and there you have it x=1. To check if this is right answer plug X back into the original problem: 1+8=9 this is a true statement so you did it right.
Just solve for x
Level: Middle school
Topic: Linear equations