If two circles x2 + y2 - 4x - 2y - 4 = 0 and (x + 1)2 + (y + 4)2 = r2 intersect at two distinct points, and the range of r is (α, β), then the value of αβ is:

The graph of the equation x + y = 7 will not pass through which quadrant?

The eccentricity of the hyperbola 36x2 - 64y2 = 1 is:

The equation of the directrix of the parabola y2 - 6y - 4x + 1 = 0 is: