Notice the x^-2, this is equal to 1/x^2. Then notice the y^0, any value raised to the zero power is equal to 1, ie n^0=1. So your expression is actually just:
8/x^2, the y value has no effect upon the output. They want you to evaluate, which must means calculate, the value when x=2 so:
8/(2^2)
8/4
2