' 4.[1o] Given the quadratic function f (x) = 2x2 6x 8, (i) Find the the xintercepts and y-intercept of the graph off. (ii) Find the coordinates of the vertex of the graph of f. (iii) Sketch the graph of f. Label the axes properly, show the correct general shape of the graph and make sure that the coordinates of the intercepts and the vertex are . correct; (iv) State the range of f