Consider the following parametric equations. x=t2t+6, y=t3 - 3t Use a graphing utility to graph the curve represented by the parametric equations. (a) Use a graphing utility to find dx dy dt dt dy and at the parameter t = -1. dx dx = dt dy dt dy dx (b) Find an equation of the tangent line to the curve at the parameter t = -1. Use a graphing utility to graph the curve and the tangent line.