Let the plane P pass through the intersection of the planes 2x + 3y - z = 2 and x + 2y + 3z = 6, and be perpendicular to the plane 2x + y - z + 1 = 0. If d is the distance of P from the point (-7, 1, 1), then d2 is equal to:

If θ is the acute angle between the planes x + 2y + 2z = 0 and 2x - 2y + z = 0, then cos(θ) is equal to:

Find the vector equation for the line passing through the points A(2, 1, 5) and B(4, 5, 7).

Find the angle between the pair of lines given by: r = î - 2ȷ - 4k̂ + λ(-2î + 2ȷ + k̂) and r = 4î + ȷ - 3k̂ + μ(2î - 4ȷ - 3k̂).