To simplify the given expression \((x^2 - 9)/(x^2 - 4) \cdot (4x - 8)/(12x + 36)\), we will first factor all the polynomials involved.
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Factor \(x^2 - 9\) and \(x^2 - 4\):
- \(x^2 - 9\) is a difference of squares: \(x^2 - 9 = (x - 3)(x + 3)\)
- \(x^2 - 4\) is also a difference of squares: \(x^2 - 4 = (x - 2)(x + 2)\)
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Factor \(4x - 8\) and \(12x + 36\):
- \(4x - 8\) can be factored out as \(4(x - 2)\)
- \(12x + 36\) can be factored out as \(12(x + 3)\)
Now substituting back into the expression, we have:
\[ \frac{(x - 3)(x + 3)}{(x - 2)(x + 2)} \cdot \frac{4(x - 2)}{12(x + 3)} \]
- Combine the fractions:
\[ \frac{(x - 3)(x + 3) \cdot 4(x - 2)}{(x - 2)(x + 2) \cdot 12(x + 3)} \]
- Cancel out common factors:
- The \(x - 2\) in the numerator and denominator can cancel.
- The \(x + 3\) in the numerator and denominator can cancel.
This results in:
\[ \frac{(x - 3) \cdot 4}{12(x + 2)} = \frac{4(x - 3)}{12(x + 2)} = \frac{(x - 3)}{3(x + 2)} \]
Thus, after simplification, the expression reduces to:
\[ \frac{x - 3}{3(x + 2)} \]
So the simplest form of the expression is:
\(\frac{x - 3}{3(x + 2)}\)
This corresponds to the option provided:
\( \frac{x - 3}{3(x + 2)} \).