is there a formula for finding a rational function of a given graph?

Question

the graph has two lines - the first line crosses the x-axis and y-axis at (0,0) and another point on that line looks to be (1,-4).  The second line crosses x-axis at (5,0) never touching y-axis anywhere else,  another point for that line is  (4,-1)  how do you find a rational function?

Answer 1

First you have to graph the lines.  Then you can see if there is any function to discribe them.

 

 

Since these lines do not have limits as the domain and range I would say that there is not a feunction to describe them.  Due to the fact that y has 2 values at all negative numbers and on the y-axis.

f(x) = {y = -1/4x,   -3 <= x < 1}

          {y = x - 5,     1 <= x < infinity.

Comments

I'm not quite getting this.  My graph has two lines that curve away from each other - they never touch and they look to be completely opposite of each other.  The verticle asymptote passes through x-axis at 2  and the horizontal asymptote passes through y-axis at 1.