Find $\displaystyle \frac{dw}{ds}(-2,2)$ and $\displaystyle \frac{dw}{dt}(-2,2) $ if $\displaystyle w= xy -yz -5xz, $ where $\displaystyle x = st, y = e^{st}, z= t^2 $

I'm confused since only two coordinates are given but the problem has 3 variables $\displaystyle x,y, z $