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The polynomial equation (ax2+bx+c)(ax2–dx–c) = 0 , ac ≠ 0 has 

(a) four real roots

(b) atleast two real roots

(c) atmost two real roots

(d) No real roots 

1 Answer

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Best answer

Correct option  (b) atleast two real roots 


ac  0

ac > 0 or ac < 0

Now D1 = b– 4ac & D2 = d2+ 4ac

When ac > 0 

D2  > 0 but D1 may positive or negative

When ac < 0

D1 > 0 but D2 may be positive or negative

In either case the polynomial has atleast two real roots 

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