#### Answer

Assume $x^{2}$ $=$ 25. Then, through algebra, we find $x$ = 5. This contradicts the given statement. Thus, the assumption $x^{2}$ $=$ 25 is false, and it follows that $x$ $\ne$ $5$.

#### Work Step by Step

Work cannot be shown for a proof. Logic is the only work done in such instances. Such work takes place mentally, and therefore cannot be shown.