Let the curve be defined by x2+xy+y2=7 and consider the point R(1,2).
a. Confirm that R lies on the curve.
b. Compute dxdy at R.
c. Express the tangent line at R in parametric form with parameter t, choosing t=0 to correspond to the point R. Provide both x(t) and y(t). (For example, you may write x(t)=… and y(t)=….)