UPSC NDA Math Model Paper 10

Given lines are:
2x - y = 1 ...(i)
x + 2y = 3 ...(ii)
Adding 2 × (i) to (ii)
⇒ 5x = 5
⇒ x = 1
Putting value of x in (i)
2(1) - y = 1
⇒ y = 1
The intersection is (1, 1)
So line has the slope -2 and passes through (1, 1)
∴ Equation of the perpendicular line is
(y−y1)=m(x−x1)
⇒y−1=−2(x−1)
⇒y+2x−3=0