because y^3 is raised to the power of two, we will have to multiply the exponents rather than adding them.
By distributing the power of 2, we will get y^2(6).
Because now the exponents are being multiplied, we can just add them to get y^8. The other y has a power of 1, so we'll just add the power of that y as well to get y^9.
summary:
multiply exponents if they are being raised to a power.
add exponents if they are being multiplied, and only add them if they have the same base (in this case, both the bases of the exponents are y, so we can add them)
