Aeroplane travels from cityA (200,-100) to cityA (500,-700) on route is a detection tower find the parametric equation of the line and then find square distance closest to detection tower on line of flight.I have found the equation of the line which is 300t+200 cityAand -600t-100 cityB the equation ore line is -2x+300 but I can not seem to find the parametric equation for the detection tower to then put in to squaure form of x and y then complete the square to find the distance closest to the detection tower horizontal to directly below the aeroplane to the nearest kilometre, if you could explain How to find the equation for the detection tower.