a$)$ What do we mean by $y^{-8}$ in terms of positive exponents? Give a general formula for expressing negative exponerats in terms of positive exponents, i$.$eo$,$ state

$y^{-n}=$

b$)$ Write with positive exponents only. Show your work and circle the correct choice.

$\frac{x^{-5}*y^4}{x^2*y^{-3}*z}=$