(a) Consider the equation y = x² - 2x. What curve does this represent in R²? Make a sketch of the curve. (b) What surface does the equation in (a) above represent in R³? Make a sketch of the surface. (c) If we now had the equation z = y²-2y, describe the features of this surface in R³, and describe how we could use the answer to (b) above to answer this question. Sketch what the surface looks like.