The equation of a curve is y = 8x-x. (i) Express 8x-x in the form a- (x+b), stating the numerical values of a and b. (ii) Hence, or otherwise, find the coordinates of the stationary point of the curve. (iii) Find the set of values of x for which y > -20. The function g is defined by g: x8x-x, for x>4. (iv) State the domain and range of g. (v) Find an expression, in terms of x, for g (x).