how to solve Question 9

9. Given the curve x + =xy + y = 60 a) Find the general expression for the slope of the curve b) Find the coordinates of the points on the curve where the tangents are horizontal. 10. Consider the curve defined by - 8x + 5xy + y =-149 a) Find dy dx b) Write an equation for the line tangent to the curve at the point (-1, 4). Solve for a and k. 1 1. The slope of the tangent is -1 at (0,1) on x3 - 6xy - ky = a, where k and a are constants Page 3 3 +