find ds/dt at (2,1) given t6(2)-2ts+s^(2)=s
possible choices are -2/3, 2/3, -3/2 or 3/2
Is t6^(2) supposed to be t^2 ?
Looks like you missed the shift key.
Consider s to be a function of t and differentiate both sides of the equation with respect to t.
This is called implicit differentiation.