The foot of the perpendicular drawn from the point 5,4 on the line whose equation is X=0
−5,4
5,0
0,4
0,-4
The foot of the perpendicular of a point (a,b) on x=0, it means on y−axis is (0,b)
Therefore, the foot of the perpendicular of a point (5,4) on x=0,(y−ax is ) axis is (0,4)