2x2 - 3xy - 2y2 = 0 represents two lines L1 and L2. 2x2 - 3xy - 2y2 - x + 7y - 3 = 0 represents another two lines L3 and L4. Let A be the point of intersection of lines L1, L3 and B be the point of intersection of lines L2, L4. The area of the triangle formed by lines AB, L3, and L4 is:

Let PQR be a right-angled isosceles triangle, right-angled at Q(2, 1). If the equation of the line PR is 2x + y = 3, then the combined equation representing the pair of lines PQ and QR is:

If the angle between the lines joining the origin to the points of intersection of x + 2y + λ = 0 and 2x2 - 2xy + 3y2 + 2x - y - 1 = 0 is π/2, then a value of λ is: