(A) We have λ2+(λ+2)2<4
⇒2λ2+4λ<0
⇒λ(λ+2)<0
⇒−2<λ<0
∴−12∈(−2,0)
and −1∈(−2,0)
Options (1,2) are correct.
(B) We have
λ2+(λ+2)2−2λ+4(λ+2)>0
⇒2λ2+6λ+12>0
⇒λ2+3λ+6>0
⇒λ2+3λ+6=0
⇒(λ+32)2+154>0
∴ All options are correct.
(c) For both the circles r>0
⇒√λ2−4>0 and √(2λ2−8)>0
Squaring both sides, we get
λ2−4>0 and λ2−4>0
∴λ2>4
⇒λ<−2 and λ>2
∴λ∈(−∞,−2)∪(2,∞)
Options (4,5) are correct.