AP EAMCET Engineering 22 Apr 2019 Shift 1 Paper

Consider the equation of circle,
x2+y2+2λx−2λy+λ2=0
Here, the center is (−λ,λ) and radius is λ
The circle touches 12x+5y−60=0 so, r=d
This implies,
λ=

|−7λ−60|

√144+25

13λ=|−7λ−60|
7λ+60=13λ or −7λ−60=13λ
6λ=60 or 20λ=−60
λ=10 or λ=−3
As radius cannot be negative therefore,
lambda=10