Each of the numbers 1, 2, 3 and 4 is substituted, in some order for p, q, r and s. The greatest possible value of pq+rs is:
Find the value of k if PQ and RS are parallel, given P(1, 2), Q(4,5) and R(3, 4), S(8, k).
Find the value(s) of k so that PQ will be parallel to RS. Given :
(i) P (2, 4), Q (3, 6), R (8, 1) and S (10, k) (ii) P (5, -1), Q (6, 11), R (6, -4k) and S (7, k2)