Lets start a conversation cuase im bored yes bored

Asystem of equations has 1 solution.if 4x-y=5 is one of the equations , which could be the other equation ?

Abird on top of a 200 ft bridge tower sees a man standing on the lower part of the bridge (which is 50 ft above the ground). the angle of depression from the bird is 26 ̊. how far is the man from the base of the bridge tower? with explanation and pictures .

What is the the greatest common factor ?