You just need to plug the values: you have to multiply [tex] x [/tex] and [tex] y^2 [/tex], and then divide the result by -3.
So, if [tex] y=2 [/tex], we have [tex] y^2=4[/tex]
Which means that [tex] xy^2 = 5\cdot 4 = 20 [/tex]
And the final answer is [tex] \frac{20}{-3} [/tex]
