f (x) = ax+b (x-1) (x-9) has a horizontal tangent at (3, -1). Determine the values of a and b.Rewrite each function as a sum or difference of terms of the form c.x", where n is a rational number, differentiate, and then simplify (no negative exponents!) [KU: /5] y = 12x2 - 6 Vx -=+7 (2 marks) 12x3-9x +6 a) b) y = (3 marks) X