For function y = x2 -6x + 8, carry out the given tasks:
i) Put function in form y =a(x - h)2 + k.
ii) Determine equation for line of symmetry for graph of function?
iii) Graph function using equation in part i. Describe why it is not essential to plot points to graph when using y = a (x - h)2 + k. Illustrate graph. Explain graphing.