To simplify the given expression, we need to follow these steps:
Factorize the denominators and numerators where possible.
Cancel out common factors in the numerator and the denominator.
Simplify the resulting expression.
Step 1: Expression Setup
We start with the expression:
\[
\frac{x + 2y}{24x^2} \cdot \frac{3x}{x^2 + xy - 2y^2}
\]
Step 2: Simplification
First, we can rewrite the expression as:
\[
\frac{(x + 2y) \cdot 3x}{24x^2 \cdot (x^2 + xy - 2y^2)}
\]
Next, we simplify the numerator and denominator. The numerator becomes:
\[
3x(x + 2y)
\]
And the denominator is:
\[
24x^2(x^2 + xy - 2y^2)
\]
Step 3: Factorization
We can factor the denominator \(x^2 + xy - 2y^2\). The expression simplifies to:
\[
\frac{3x(x + 2y)}{24x^2(x - y)(x + 2y)}
\]
Here, we notice that \(x + 2y\) cancels out from the numerator and denominator.
Step 4: Final Simplification
After canceling \(x + 2y\), we have:
\[
\frac{3}{24x(x - y)} = \frac{1}{8x(x - y)}
\]
Final Answer
The simplified expression is:
\[
\boxed{\frac{1}{8x(x - y)}}
\]