(a)[2]
Find the derivative of $y$ in terms of $x$.
(b)[4]
Find the equation of the tangent to the graph of $y=x^7-7x^6$ at $x=-1$. Give the answer in the form $y=mx+c$.
(c)[5]
Two turning points lie on the graph of $y = x^7 - 7x^6$. Find the coordinates of these points. You must show all your working.