Complex Numbers And Quadratic Equations question 720
Question: The number which exceeds its positive square root by 12 is
Options:
A) 9
B) 16
C) 25
D) None of these
Show Answer
Answer:
Correct Answer: B
Solution:
Let the required number is x So, $ x=\sqrt{x}+12\Rightarrow x-12=\sqrt{x} $
Þ $ x^{2}-25x+144=0 $
Þ $ x^{2}-16x-9x+144=0 $
$ \Rightarrow x=16 $ Since $ x=9 $ does not hold the condition. Trick: By inspection, since 16 exceeds its positive square root i.e.,4 by 12.
BETA
