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MathematicsQuadratic EquationCommon RootsHard2 minPYQ_2022
MathematicsHardnumerical

Letfxbe a quadratic polynomial with leading coefficient1such thatf0=p,p0, andf1=13. If the equationsfx=0andfofofofx=0have a common real root, thenf-3is equal to ______.

Answer:
25.00
Solution:

Let fx=x-αx-β

It is given that f0=pαβ=p

and f1=13   1-α1-β=13

Now let us assume that α is the common root of fx=0 and fofofof x=0

fofofof x=0

fofofof α=0

 fofof 0=0

 fofp=0

So, fp is either α or β.

Now assuming p-αp-β=α

αβ-ααβ-β=αβ-1α-1β=1

β3=1 as 1-α1-β=13

So, β=3

Now finding α by putting the value of β in 1-α1-β=13,

1-α1-3=13

α=76

So, fx=x-76x-3

So, f-3=-3-76-3-3=25

Stream:JEESubject:MathematicsTopic:Quadratic EquationSubtopic:Common Roots
2mℹ️ Source: PYQ_2022

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