The circle (x-5)²+(y-3)²=5 represents all points a distance √5 from (5,3). x=3 represents all points 3 units away from the y-axis. If we substitute x=3 in the circle equation we get 4+(y-3)²=5, y-3=±1, so y=4 or 2. The required coordinates are (3,4) and (3,2).