The foot of the perpendicular from the point 1,2 on the line passing through the points5,4 and 7,4is a,b then a+b =
1
3
5
7
Equation of the line joining two points (5,4) and (7,4) is y=4, because y coordinates are same and equal to 4
Foot of the perpendicular from the point (1,2) on the line y=4 is (1,4), which is (a,b)
Hence a+b=1+4=5