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Zorluk: ZorRational and Radical Expressions and Equations

For what real values of xx is the rational expression g(x)=x33x22x2x+4x24g(x) = \frac{x^3 - 3x^2}{\frac{2}{x-2} - \frac{x+4}{x^2 - 4}} undefined? Determine these three values and enter them in the blanks below in order from least to greatest.

Cevap:The values of xx for which g(x)g(x) is undefined, ordered from least to greatest, are x=x = 【-2】, x=x = 【0】, and x=x = 【2】.

Cevap

The values of xx for which the expression is undefined, ordered from least to greatest, are 2-2, 00, and 22.
The rational expression is undefined where any constituent denominator is equal to zero, or where the entire main denominator is equal to zero. The constituent denominators are x2x-2 and x24x^2-4, which are zero when x=2x = 2 or x=2x = -2. The entire main denominator simplifies to x(x2)(x+2)\frac{x}{(x-2)(x+2)}, which is zero when x=0x = 0. Therefore, the three values of xx that make the expression undefined are 2-2, 00, and 22.

Adım Adım Çözüm

1
Identify the values of xx that make the denominators of the individual rational terms equal to zero.
The denominators are x2x - 2 and x24x^2 - 4. Setting these to zero gives x=2x = 2 and x=±2x = \pm 2. Thus, x=2x = 2 and x=2x = -2 are values that make the individual terms undefined.
Any rational term is undefined if its denominator is equal to zero.
2
Find the values of xx that make the overall denominator of the main fraction equal to zero by first simplifying it.
The main denominator is 2x2x+4x24\frac{2}{x-2} - \frac{x+4}{x^2-4}. Finding a common denominator yields 2(x+2)(x+4)(x2)(x+2)=x(x2)(x+2)\frac{2(x+2) - (x+4)}{(x-2)(x+2)} = \frac{x}{(x-2)(x+2)}. Setting this equal to zero gives x=0x = 0.
The main rational expression is undefined if its entire denominator is equal to zero.
3
Combine all restricted values and list them in order from least to greatest.
The restricted values are x=2x = -2, x=0x = 0, and x=2x = 2.
These are all the distinct real numbers that cause any division by zero in the original expression.

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Finding the domain of nested rational expressions
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