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