If P(x,y) is a point on the line y=−3x such that P and Q(3,4) are on opposite side of the line 3x−4y=8, then
Factorise
(i) x2 + xy + 8x + 8y
(ii) 15xy − 6x + 5y − 2
(iii) ax + bx − ay − by
(iv) 15pq + 15 + 9q + 25p
(v) z − 7 + 7xy − xyz
Let PQR be a right angled isosceles triangle right angled at P(2,1). If the equation of the line QR is 2x+y=3, then the equation representing the pair of lines PQ and PR is