First the student needs to differentiate the function to find dy/dx = 2x-6At dy/dx = 0, we know the curve is stationary. Now we can work out the x value such that x = 3Put x=3 back into the original equation to get y = -4.To find whether the value is min or max, we must further differentiate dy/dy to get d^2y/dx^2 = 2Since this is greater than 0, the curve is a minimum.