How do you write an equation in slope intercept form given that the line passes through (-4,-1) and (2,-1)?

$y = - 1$
Since the value of y does not change for points on a line between $\left(- 4 , - 1\right)$ and $\left(2 , - 1\right)$
the slope of a line through the points $\left(- 4 , - 1\right)$ and $\left(2 , - 1\right)$ is $0$
the equation of the line is $y = - 1$