Q. 9

# Mark the correct alternative in the following:If , then a =A. 2B. 3C. 4D. none of these

a2 – a = 2 + 4 ( nCx = nCy n = x + y or x = y )

a2 – a – 6 = 0

a2 – 3a – 2a – 6 = 0

a(a – 3) + 2(a – 3) = 0

(a + 2) (a – 3) = 0

a = -2 or a = 3

But, a = -2 is not possible since it’s negative.

So, a = 3.

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