JEE Main 2020MathematicsFunctionsMediumMCQ

JEE Main 2020 — Functions Question with Solution

JEE Main 2020 (07 Jan Shift 1)

Question

If gx=x2+x-1 and gofx=4x2-10x+5, then f54 is equal to

Choose an option

Show full solutionCorrect option: B
Correct answer
B-12

Step-by-step explanation

gfx=4542-10.54+5=-54
gf54=f254+f54-1
-54=f254+f54-1
f254+f54+14=0
f54+122=0
f54=-12

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About this question

This is a previous-year question from JEE Main 2020, covering the Functions 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.