To solve the expression \(\sqrt{81 x^{14}}\), we need to simplify the square root of the product of a constant and a variable raised to a power. We can break it down into the square root of the constant and the square root of the variable part separately.
Solution Approach
Simplify the square root of the constant 81.
Simplify the square root of \(x^{14}\) by using the property \(\sqrt{x^n} = x^{n/2}\).
Step 1: Simplify the Constant
We start with the expression \( \sqrt{81 x^{14}} \). The square root of the constant 81 can be simplified as follows:
\[
\sqrt{81} = 9
\]
Step 2: Simplify the Variable Part
Next, we simplify the square root of the variable part \( x^{14} \):
\[
\sqrt{x^{14}} = x^{14/2} = x^7
\]
Step 3: Combine the Results
Now, we combine the results from the previous steps:
\[
\sqrt{81 x^{14}} = 9 \cdot x^7
\]
Final Answer
Thus, the simplified expression is
\[
\boxed{9x^7}
\]