First, we have to move the constant to the other side. By moving it to the other side, the sign also changes becoming -3x < 23 - 8.
Now we simplify: 23 - 8 becomes 15
New equation: -3x < 15
Finally, we want the X by itself, and to do that, we must divide -3 to both sides. Keep in mind that when we multiply or divide, the sign '<' also changes.