1. The problem is to simplify or understand the expression $\sqrt{x}$. 2. The square root function $\sqrt{x}$ is defined as the number which, when multiplied by itself, gives $x$. 3. Important rule: $\sqrt{x^2} = |x|$, meaning the square root of a square is the absolute value of $x$. 4. If $x$ is a perfect square, say $x = a^2$, then $\sqrt{x} = a$. 5. If $x$ is not a perfect square, $\sqrt{x}$ remains as is, representing the principal (non-negative) square root. 6. For example, $\sqrt{9} = 3$ because $3^2 = 9$. 7. If $x$ is negative, $\sqrt{x}$ is not a real number (in real numbers), but can be expressed in complex numbers as $\sqrt{-1} = i$. Final answer: $\sqrt{x}$ is the principal square root of $x$, defined for $x \geq 0$ in real numbers.