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If the equation a x^2+b x+c=x has no rea...

If the equation `a x^2+b x+c=x` has no real roots, then the equation `a(a x^2+b x+c)^2+b(a x^2+b x+c)+c=x` will have a. four real roots b. no real root c. at least two least roots d. none of these

A

four real roots

B

no real root

C

al least two real roots

D

None of these

Text Solution

Verified by Experts

The correct Answer is:
2

Since ` ax^(2) + bx + c = x ` has no real roots
`rArr ax^(2) + bx + c gt x or ax^(2) + bx + c lt x ` for all real x .
Let `ax^(2) + bx + c gt x and ax^(2) + bx + c = p(x)`
` therefore P(x) gt x ` for all real x,
`rArr P(P(x)) gt P(x)`
`rArr a(ax^(2) + bx + c )^(2) + b (bx^(2) + bx + c) + c gt ax^(2) + bx + c gt x `
Hence , given equation has no real solution.
Similarly it can be proved for `ax^(2) + bx + c lt x `
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