Suppose the two chords, drawn from the point (1, 2) on the circle x2+y2+x−3y=0 are bisected by the y-axis. If the other ends of these chords are R and S, and the mid point of the line segment RS is (α,β), then 6(α+β) is equal to :
(A)1
(B)3✓ Correct
(C)4
(D)6
Answer: (B)
Solution
The point P(1,2) lies on the circle since 1+4+1−6=0. A chord from P whose midpoint is (0,λ) on the y-axis has its other end S=2(0,λ)−(1,2)=(−1,2λ−2). Requiring S on x2+y2+x−3y=0 gives 1+(2λ−2)2−1−3(2λ−2)=0, i.e. (2λ−2)(2λ−5)=0, so λ=1 or λ=25. The two other ends are (−1,0) and (−1,3), whose midpoint is (α,β)=(−1,23). Thus 6(α+β)=6(−1+23)=3.
JEE Main · 2026 · 04 Apr 2026 · Shift 1 · Single correct option