Theory of Equations 1 Question 42

43. If P(x)=ax2+bx+c and Q(x)=ax2+bx+c, where ac0, then P(x)Q(x) has atleast two real roots.

(1985,1M)

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Answer:

Correct Answer: 43. (True)

Solution:

  1. P(x)Q(x)=(ax2+bx+c)(ax2+bx+c)

Now, D1=b24ac and D2=b2+4ac

Clearly, D1+D2=2b20

Atleast one of D1 and D2 is (+ ve). Hence, atleast two real roots.

Hence, statement is true.



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