Which rational expression has a value of 1 when [tex][tex]$x = -1$[/tex][/tex]?

A. [tex]\frac{3x - 2}{x^2 + 5}[/tex]

B. [tex]\frac{-4x + 3}{x^2 - 8}[/tex]

C. [tex]\frac{3x - 4}{6x^2}[/tex]

D. [tex]\frac{2x^2}{x + 3}[/tex]



Answer :

To determine which of the given rational expressions equals 1 when [tex]\(x = -1\)[/tex], let's evaluate each expression step-by-step at [tex]\(x = -1\)[/tex].

1. For the expression [tex]\(\frac{3x - 2}{x^2 + 5}\)[/tex]:
[tex]\[ \frac{3(-1) - 2}{(-1)^2 + 5} = \frac{-3 - 2}{1 + 5} = \frac{-5}{6} \][/tex]
The value is [tex]\(\frac{-5}{6}\)[/tex]. This is not equal to 1.

2. For the expression [tex]\(\frac{-4x + 3}{x^2 - 8}\)[/tex]:
[tex]\[ \frac{-4(-1) + 3}{(-1)^2 - 8} = \frac{4 + 3}{1 - 8} = \frac{7}{-7} = -1 \][/tex]
The value is [tex]\(-1\)[/tex]. This is not equal to 1.

3. For the expression [tex]\(\frac{3x - 4}{6x^2}\)[/tex]:
[tex]\[ \frac{3(-1) - 4}{6(-1)^2} = \frac{-3 - 4}{6 \cdot 1} = \frac{-7}{6} \][/tex]
The value is [tex]\(\frac{-7}{6}\)[/tex]. This is not equal to 1.

4. For the expression [tex]\(\frac{2x^2}{x + 3}\)[/tex]:
[tex]\[ \frac{2(-1)^2}{-1 + 3} = \frac{2 \cdot 1}{2} = \frac{2}{2} = 1 \][/tex]
The value is [tex]\(1\)[/tex]. This is the expression we are looking for.

Therefore, the rational expression that equals 1 when [tex]\(x = -1\)[/tex] is [tex]\(\frac{2x^2}{x + 3}\)[/tex].