1. Find an equation of the tangent line to the graph of the function at the given point. xy+yx=-6 (2. - 1) 2. Suppose that f (x) = (x' -2x)'. Find /"(1). 3. Determine the third derivative of g(x) =- 7 4. Find yay for xy' + 4 xy = 10. dix 5. Suppose that x and y are both differentiable functions of t. Use the given value to find dy / dt and dx / di. xy =4 a) dy when x = 8, 41= 10 di b) dx when x = 1, dy =-6 dt dt 6. The profit P from selling x units of a product is given by P=510-0.3.x . The sales are increasing at a rate of 9 units per day. Find the rate of change of the profit when x = 600 and x =800 units