11 - Equations and Inequalities Questions Answers

The maximum number of real roots of the equation 2x88 + 3x87 − 13x2 + 5x + 9 = 0 is

Asked By: HIMANSHU MITTAL
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Joshi sir comment

 

2x88 + 3x87 − 13x2 + 5x + 9 = 0

implies that 2x88 + 3x87 = 13x2 - 5x - 9

or x87(2x+3) = 13x2 - 5x - 9

now plot the left and right graphs for getting the intersecting points

Hint: Parabola will face in upward direction as a is positive, take x=0 we get -9 so 1 root will be positive and 1 negative,

x87(2x+3) will be 0 for x = -3/2 and x = 0 besides it consider some values as x = 1 and -1

You will get one root between 0 and -1 

now check both the graph at x= -2, you will get the idea about the second intersection

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