This is a horizonal line going through y = 4.
Horizontal lines are of the form
Where
a is a number
Slope is rise over run, or, the change in y divided by change in x.
No matter what the change in x is, the change in y is always zero (horizontal line). Thus, the slope is always 0 as well.
1.
The slope of the line is 0
2.
The slope intercept form is:
Since the slope is zero, m = 0 and y intercept (b) is 4, we have: