Answer:
The correct option is 2.
Step-by-step explanation:
The given function is
[tex]f(x)=ax+b[/tex]
Where, a and b are positive numbers.
The given function is the slope intercept form of a linear function. Where a is the slope and b is y-intercept.
Since slope is positive therefore function approaches to infinity as x approaches to infinity and function approaches to negative infinity as x approaches to negative infinity.
It is also proved by using limits.
[tex]lim_{x\rightarrow \infty}f(x)=lim_{x\rightarrow \infty}(ax+b)[/tex]
Apply limits.
[tex]lim_{x\rightarrow \infty}f(x)=a(\infty)+b=\infty[/tex]
Similarly,
[tex]lim_{x\rightarrow -\infty}f(x)=lim_{x\rightarrow -\infty}(ax+b)[/tex]
Apply limits.
[tex]lim_{x\rightarrow -\infty}f(x)=a(-\infty)+b=-\infty[/tex]
Therefore option 2 is correct.
[tex]f(x)\rightarrow \infty \text{ as }x\rightarrow \infty[/tex]
[tex]f(x)\rightarrow -\infty \text{ as }x\rightarrow -\infty[/tex]
