A function h:R→R is defined by h(x)=∣x2−6x+8∣.
a. (i) Factorise x2−6x+8 and identify the intervals on which this quadratic expression is non-negative and negative.
b. (ii) Using the result of part (i), rewrite h(x) as a piecewise function without the modulus sign.
c. (iii) Determine the range of h by analysing the two pieces obtained in part (ii).