Example

Example of Multiplying the Rational Functions f(x)=x2x3x2+27x30f(x) = \frac{x^2 - x}{3x^2 + 27x - 30} and g(x)=x2100x210xg(x) = \frac{x^2 - 100}{x^2 - 10x}

To find the product R(x)=f(x)g(x)R(x) = f(x) \cdot g(x) of the rational functions f(x)=x2x3x2+27x30f(x) = \frac{x^2 - x}{3x^2 + 27x - 30} and g(x)=x2100x210xg(x) = \frac{x^2 - 100}{x^2 - 10x}, use the procedure for multiplying rational expressions:

Step 1. Factor each numerator and denominator completely. Remember to factor out the greatest common factor first, if applicable: R(x)=x(x1)3(x+10)(x1)(x10)(x+10)x(x10)R(x) = \frac{x(x - 1)}{3(x + 10)(x - 1)} \cdot \frac{(x - 10)(x + 10)}{x(x - 10)}

Step 2. Multiply the numerators and denominators together: R(x)=x(x1)(x10)(x+10)3x(x+10)(x1)(x10)R(x) = \frac{x(x - 1)(x - 10)(x + 10)}{3x(x + 10)(x - 1)(x - 10)}

Step 3. Simplify the expression by dividing out the common factors of xx, (x1)(x - 1), (x10)(x - 10), and (x+10)(x + 10). Since all factors in the numerator cancel, a 11 remains in the numerator, while a 33 remains in the denominator: R(x)=13R(x) = \frac{1}{3}

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Updated 2026-04-30

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