The top portion of this graph would be y = 4
The bottom portion would be y = x - 1
In order to find both of these, we have to look at them separately. Let's start with the flat line between 1 and -1. Since it is between those numbers, we know this one goes on top. We also know that since the line is horizontal, that the equation must be y = the number that it sits at. This is the definition of a horizontal line. Since the line is at 4, we get y = 4.
For the sloped portion, we have to pick two points and find the equation of the line. Let's use (3, 2) and (5, 4). We must start by finding slope (m)
m = (y1 - y2)/(x1 - x2)
m = (4 - 2)(5 - 3)
m = 2/2
m = 1
So we know slope to equal 1. Now we can use a point and slope intercept form to find the y-intercept (b)
y = mx + b
4 = 1(5) + b
4 = 5 + b
-1 = b
Now put them together in an equation for the bottom part: y = x - 1
