To simplify the given expression, we need to break down the square roots into their prime factors and then combine like terms.
Solution Approach
Simplify the square roots by factoring out perfect squares.
Combine the simplified terms.
Step 1: Simplifying the First Term
We start with the first term \( 6 \sqrt{32x} \). We can simplify \( \sqrt{32} \) as follows:
\[
\sqrt{32} = \sqrt{16 \cdot 2} = 4\sqrt{2}
\]
Thus, we have:
\[
6 \sqrt{32x} = 6 \cdot 4 \sqrt{2} \sqrt{x} = 24 \sqrt{2} \sqrt{x}
\]
Step 2: Simplifying the Second Term
Next, we simplify the second term \( -5 \sqrt{18x} \). We can simplify \( \sqrt{18} \) as follows:
\[
\sqrt{18} = \sqrt{9 \cdot 2} = 3\sqrt{2}
\]
Thus, we have:
\[
-5 \sqrt{18x} = -5 \cdot 3 \sqrt{2} \sqrt{x} = -15 \sqrt{2} \sqrt{x}
\]
Step 3: Combining the Terms
Now we combine the simplified terms:
\[
24 \sqrt{2} \sqrt{x} - 15 \sqrt{2} \sqrt{x} = (24 - 15) \sqrt{2} \sqrt{x} = 9 \sqrt{2} \sqrt{x}
\]
Final Answer
The simplified expression is:
\[
\boxed{9 \sqrt{2} \sqrt{x}}
\]