Question 181779
The slope of a horizontal line is 0
If {{{y = mx + b}}}, and m=0. then using the point given,
{{{3 = 0*(-2) + b}}}
{{{3 = b}}}

You now know both m and b, so the line's equation is
{{{y = 0*x + 3}}} or
{{{y = 3}}}