JEE MainMathematicsQuadratic Equation and InequalitiesMCQ+4 / −1
Let be in R. If and are the roots of the equation, x2 - x + 2 = 0 and and are the roots of the equation, , then is equal to:
- A36
- B9
- C27
- D18
View written solutionFree
Correct answer: D
- Interpret the given equations
We are given:
- are roots of
- are roots of
We need to find:
Also, .
- Use sum of roots
For the first equation, Sum of roots:
For the second equation, Sum of roots:
Subtracting,
But this alone is not enough. We now use product of roots.
- Use product of roots
For the first equation,
For the second equation,
Now divide the second by the first:
Since and (otherwise impossible), we get
So,
- Use the relation from sums
We have and also
Equating:
Substitute :
Hence,
- Find
From we get
Now use
- Compute the required value
- Check options
The value is So the correct option is D.
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