The distance of the point (1,−2,3) from the plane x−y+z=5 measured parallel to the line 2x=3y=−6z is:
(A)71
(B)7
(C)57
(D)1✓ Correct
Answer: (D)
Solution
A line through P(1,−2,3) parallel to the given line is 2x−1=3y+2=−6z−3=λ, so a general point on it is (2λ+1,3λ−2,−6λ+3). Requiring this to lie on the plane x−y+z=5 gives (2λ+1)−(3λ−2)+(−6λ+3)=5, so −7λ+6=5 and λ=−71. The distance is then ∣λ∣22+32+62=71⋅7=1.
JEE Main · 2020 · 04 Sep 2020 · Shift 2 · Single correct option