JEE Main 2020MathematicsStraight LinesMediumMCQ

JEE Main 2020 — Straight Lines Question with Solution

JEE Main 2020 (08 Jan Shift 1)

Question

Let two points be A1,-1 and B0,2. If a point Px', y' be such that the area of ∆PAB=5 sq. units and it lies on the line 3x+y-4λ=0, then a value of λ is

Choose an option

Show full solutionCorrect option: B
Correct answer
B3

Step-by-step explanation

∆=120211-11x'y'1 
⇒-21-x'+y'+x'=±10
⇒-2+2x'+y'+x'=±10
⇒3x'+y'=12 Or 3x'+y'=-8 ...i

x', y' lies on the line 3x+y-4λ=0,

So, 3x'+y'-4λ=0...ii

Solving i and ii, we get,
     λ=3, -2

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About this question

This is a previous-year question from JEE Main 2020, covering the Straight Lines chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.