If the slope is 0 then by definition this is a horizontal line and for and all values of x (including when x=0) y is the same. And, because we were given the y-intercept as 5 we know the equation for this line is:
y=5
Explanation:
If the slope is 0 then by definition this is a horizontal line and for and all values of x (including when x=0) y is the same. And, because we were given the y-intercept as 5 we know the equation for this line is: