Which statement describes the behavior of the function [tex]f(x)=\frac{3x}{4-x}[/tex]?

A. The graph approaches -3 as [tex]x[/tex] approaches infinity.
B. The graph approaches 0 as [tex]x[/tex] approaches infinity.
C. The graph approaches 3 as [tex]x[/tex] approaches infinity.
D. The graph approaches 4 as [tex]x[/tex] approaches infinity.



Answer :

To analyze the behavior of the function [tex]\( f(x) = \frac{3x}{4-x} \)[/tex] as [tex]\( x \)[/tex] approaches infinity, let's break down the expression step-by-step.

1. Identify Dominant Terms:
When [tex]\( x \)[/tex] becomes very large, the constant term 4 in the denominator becomes relatively insignificant compared to [tex]\( x \)[/tex]. Thus, it is useful to focus on the terms involving [tex]\( x \)[/tex] because they will dominate the behavior of the function.

2. Simplify the Expression for Large [tex]\( x \)[/tex]:
For large values of [tex]\( x \)[/tex]:
[tex]\[ f(x) = \frac{3x}{4 - x} \][/tex]
Since [tex]\( x \)[/tex] is very large, [tex]\( 4 - x \)[/tex] is approximately equal to [tex]\( -x \)[/tex]:
[tex]\[ f(x) \approx \frac{3x}{-x} \][/tex]

3. Reduce the Simplified Expression:
Dividing the numerator and the denominator by [tex]\( x \)[/tex]:
[tex]\[ f(x) \approx \frac{3}{-1} = -3 \][/tex]

4. Conclusion:
As [tex]\( x \)[/tex] approaches infinity, the function [tex]\( f(x) = \frac{3x}{4 - x} \)[/tex] approaches the value [tex]\( -3 \)[/tex].

Thus, the correct statement is:

The graph approaches [tex]\(-3\)[/tex] as [tex]\( x \)[/tex] approaches infinity.