Question

If the square of 9 is written as $\frac{x^2-1}{2}+\frac{x^2+1}{2}$, then the value of $x$ is

• A. 9

Answer 1

The correct option is A 9
Square of any odd number $n$ can be written as the sum of two consecutive natural numbers.
Those two natural numbers are $\frac{n^2-1}{2}$ and $\frac{n^2+1}{2}$ respectively.

Therefore, $9^2=\frac{x^2-1}{2}+\frac{x^2+1}{2}$.
Thus, the value of $x$ is 9.