Example

Example of Determining the Domain of the Rational Function R(x)=4x2−16x8x2−16x−64R(x) = \frac{4x^2 - 16x}{8x^2 - 16x - 64}

To find the domain of the rational function R(x)=4x2−16x8x2−16x−64R(x) = \frac{4x^2 - 16x}{8x^2 - 16x - 64}, determine which values make the denominator equal to zero and exclude them.

Step 1. Set the denominator equal to zero: 8x2−16x−64=08x^2 - 16x - 64 = 0.

Step 2. Solve the equation. Begin by factoring out the greatest common factor: 8(x2−2x−8)=08(x^2 - 2x - 8) = 0. Then, factor the trinomial: 8(x−4)(x+2)=08(x - 4)(x + 2) = 0. Apply the Zero Product Property by setting each variable factor to zero: x−4=0x - 4 = 0 or x+2=0x + 2 = 0. Solving these equations gives x=4x = 4 and x=−2x = -2.

Step 3. State the domain by excluding the values found in Step 2. Thus, the domain of R(x)R(x) is all real numbers where xeq4x eq 4 and xeq−2x eq -2.

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Updated 2026-06-18

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