Note: For full marks you must showall of your work and give awritten answer!

Let f(x) =-2x2+12x

1. Find the coordinates of the vertex for this parabola. Is the vertex a maximum or a minimum? How do you know? (4)

1. Use the difference quotient (IRC formula) for this function to identify the value of x where the slope of f(x) is zero. (4 total)

i) Find the DQ here. (2)

ii) Find the value of x where slope = 0 here. (2)