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Ch. R - Review of Basic Concepts
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 1, Problem 13a

Find the domain of each rational expression. (3x + 7) / (4x + 2)(x - 12)

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Identify the rational expression given: \(\frac{3x + 7}{(4x + 2)(x - 12)}\).
Recall that the domain of a rational expression includes all real numbers except those that make the denominator equal to zero.
Set each factor in the denominator equal to zero to find the values to exclude: solve \(4x + 2 = 0\) and \(x - 12 = 0\).
Solve \(4x + 2 = 0\) by isolating \(x\): \(4x = -2\) then \(x = -\frac{1}{2}\).
Solve \(x - 12 = 0\) by isolating \(x\): \(x = 12\). The domain is all real numbers except \(x = -\frac{1}{2}\) and \(x = 12\).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Domain of a Rational Expression

The domain of a rational expression includes all real numbers except those that make the denominator zero. Since division by zero is undefined, identifying values that cause the denominator to be zero is essential to determine the domain.
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Factoring and Setting Denominator Equal to Zero

To find values excluded from the domain, set each factor in the denominator equal to zero and solve for the variable. These solutions indicate points where the expression is undefined and must be excluded from the domain.
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Simplifying Rational Expressions

Simplifying rational expressions by factoring helps identify restrictions on the domain clearly. It also aids in understanding the behavior of the expression near excluded values and ensures the domain is accurately described.
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