Examine the quadratic trinomial x2+kx+(k−4), where k is an integer.
a. (i) Determine all integer values of k for which the trinomial can be factorised over the integers.
b. (ii) Among the values obtained in part (i), find the value(s) of k for which the trinomial is a perfect square.
c. (iii) Verify your result in part (ii) by writing the factorised form of the trinomial.