4. The graph of the equation y* = y' -x is shown at right. (a) Verify that - dy 2x Show the work that leads to your answer. dx 2y-4y- (b) Find the point(s) (x. y) at which the graph has a horizontal tangent line. Show the work that leads to your answer. (c) Find the y-value(s) which the graph has a vertical tangent line. Show the work that leads to your answer. (d) While the graph exists at (0,0), the slope does not. Using 1 y,explain why this is so.5. Consider the curve given by 6+ x y=zy (a) Show that dx x -2xy (b) Find every point(s) on the graph of the curve that has an x-coordinate of 1, then write an equation for the tangent line at every/cach of these point(s). (c) The graph of the curve has vertical tangent lines. Find the x-coordinate of each of these vertical tangent lines. Show the work that leads to your answer.