So this, we could rewrite this, we could write this as nine x to the 4 3rd power. So if we evaluate it at eight, this is going to be nine times eight to the 4 3rds power, and from that, we're going to subtract, it evaluated at negative one. So this is going to be nine times negative one to the 4 3rd power. So what is eight to the 4 3rd power? I'll do it over here. So eight to the 4 3rds is equal to eight to the 1 3rd to the 4th power. These are just exponent properties here.