The expression you provided is \(\sqrt{-36}\).
Step 1: Understanding Square Roots
The square root of a number \(x\) is a value \(y\) such that \(y^2 = x\). This means that for a square root to be a real number, \(x\) must be greater than or equal to zero.
Step 2: Analyzing the Given Expression
In this case, you have \(\sqrt{-36}\). Since \(-36\) is less than zero, it does not have a real square root.
Step 3: Using Imaginary Numbers
However, in mathematics, the square root of a negative number can be expressed using imaginary numbers. The square root of \(-1\) is denoted as \(i\). Therefore:
\[ \sqrt{-36} = \sqrt{-1 \cdot 36} = \sqrt{-1} \cdot \sqrt{36} = i \cdot 6 = 6i \]
Conclusion
Since \(\sqrt{-36}\) results in an imaginary number (not a real number), the correct response is:
B. The expression is not a real number.