Write the set of values of 'a' for which the equation x2 + ax – 1 = – InterviewSolution

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1.

Write the set of values of 'a' for which the equation x2 + ax – 1 = 0 has real roots.

Answer»

Consider x² + ax – 1 = 0,For the quadratic equation to have real roots D ≥ 0

Here a = 1, b = a and c = 1

In the given equation D = a² – 4 ≥ o

⇒ a² ≥ 4

So for all the real values of ‘a’ which are greater than or equal to 2 and – 2 the equation will have the real roots.

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