Answer:
[tex]y^7[/tex]
Step-by-step explanation:
If we want to simplify the expression [tex]y^9 \cdot y^{-2}[/tex], we have to note that exponent rules state that [tex]x^a \cdot x^b = x^{a+b}[/tex].
This means that if we add the exponents, that will be what we raise y to the power of.
[tex]9 + -2 = 9-2 = 7[/tex]
So [tex]y^7[/tex].
Hope this helped!