If the points with coordinates (-5, 0), (5p², 10p) and (5q², 10q) are collinear, then what is the value of pq where p ≠ q ?

What is the equation of the straight line which passes through the point (1, -2) and cuts off equal intercepts from the axes ?

What is the equation of the circle which touches both the axes in the first quadrant and the line y - 2 = 0?

What is the equation of the parabola with focus (-3, 0) and directrix x - 3 = 0 ?