Suppose A,B are two points on 2x−y+3=0 and P(1,2) is such that PA=PB . Then the mid-point of AB is

In an Isosceles triangle median is the altitude Equation of AB=2x−y+3=0⇒ ΔPAD≅△PBD⇒D is foot of perpendicular ⇒ from P to AB α−12=β−2−1=−(2×1−1×2+3)4+1 α−12=β−2−1=−35⇒α=−15,β=135