Answer:
I guess that the expression is:
(y^2*y^3)/(y*y^(-2))
remember this two relationships.
a^x*a^y = a^(x + y)
(a^x)/(a^y) = a^(x - y).
then we have:
y^2*y^3 = y(2 + 3) = y^5.
and
y*y^(-2) = y^(1 + (-2)) = y^-1
then our expression can be written as:
(y^2*y^3)/(y*y^(-2)) = y^5/y^(-1) = y^(5 - 1) = y^4.
Then the correct option is b: y^4