Q6 of 242 Page 9

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

For the quadratic equation to have real roots D 0

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


d = b2 – 4ac


In the given equation d = a2 – 4 ≥ o


D = a ≥ 2


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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