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Question: Answered & Verified by Expert
If the graph of the function y=a-b2x2+2a+b-2cx+1 ab is strictly above the x-axis, then
MathematicsQuadratic EquationJEE Main
Options:
  • A a<b<c
  • B a<c<b
  • C b<a<c
  • D c<b<a
Solution:
1288 Upvotes Verified Answer
The correct answer is: a<c<b
D=B2-4AC
=2a+b-2c2-4a-b2
=4a+b-2c2-a-b2
=4a+b-2c-a+ba+b-2c+a-b
=42b-2c2a-2c
=16b-ca-c
=16c-bc-a
If c lies between a and b, then D is negative. Hence, the roots will be imaginary and the graph will be entirely above the x-axis as the coefficient of x2 is positive.

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