Q9 of 13 Page 107

If a positive number exceeds its positive square roots by 12 then find the number.

Let the positive number be ‘a2’, then ’a’ is its positive square root


a2 – a = 12


⇒ a2 – a - 12 = 0


⇒ a2 – 4a + 3a – 12 = 0


⇒ a(a – 4) + 3(a – 12) = 0


⇒ (a + 3)(a – 4) = 0


⇒ a = 4, -3


Given, a is positive.


∴ a = 4


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