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Zorluk: OrtaRational and Radical Expressions and Equations

The rational expression x3x2x12\frac{x - 3}{x^2 - x - 12} is undefined for two real values of xx. What are these two values, where the smaller value is entered in the first blank and the larger value is entered in the second blank?

Cevap:The smaller value is 【-3】 and the larger value is 【4】.

Cevap

The expression is undefined when the smaller value is -3 and the larger value is 4.
A rational expression is undefined when the denominator is equal to 00. For the expression x3x2x12\frac{x - 3}{x^2 - x - 12}, setting the denominator equal to zero gives x2x12=0x^2 - x - 12 = 0. Factoring the quadratic expression yields (x4)(x+3)=0(x - 4)(x + 3) = 0. Setting each factor to zero gives the solutions x=4x = 4 and x=3x = -3. Thus, the smaller value for which the expression is undefined is 3-3 and the larger value is 44.

Adım Adım Çözüm

1
Identify the condition that makes a rational expression undefined.
A rational expression is undefined when its denominator is equal to zero.
Division by zero is undefined in real numbers.
2
Set the denominator of the expression equal to zero.
x2x12=0x^2 - x - 12 = 0
This equation will yield the values of xx for which the denominator is zero.
3
Factor the quadratic equation.
(x4)(x+3)=0(x - 4)(x + 3) = 0
Factoring allows us to find the roots by setting each linear factor to zero.
4
Solve for xx by setting each factor equal to zero.
x=4x = 4 or x=3x = -3
If x4=0x - 4 = 0, then x=4x = 4. If x+3=0x + 3 = 0, then x=3x = -3.
5
Identify the smaller and larger values.
The smaller value is 3-3 and the larger value is 44.
Comparing the two values, 3<4-3 < 4.

Anahtar Kavram

Identifying values that make a rational expression undefined by finding the roots of the denominator.
Tahmini Süre:1m 15s
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