∵‌‌x+y=3 and x−y=3 are tangents ∴‌‌ Both circle centre will lie on x-axis ∴‌‌(x−a)2+y2=r2 Hence centre is C(α,0) r=√(α+9)2+16 Also |‌
α−3
√2
|=r ‌√(α+9)2+16=|‌
α−3
√2
| ‌⇒‌‌α=−5‌ or ‌−37 ‌r=|‌
−5−3
√2
|‌ or ‌|‌
−37−3
√2
| ‌=4√2‌ or ‌20√2 ‌|r12−r22|=|32−800|=768