HOY -- horizontal line, 0 slope, represented by y = a number....with that number being the y values of ur points
so ur equation would be : y = 0x - 3 which can be written as y = -3
and just so u know, if u didn't have the graph and u just had ur points
(-2,-3),(3,-3)...when ur y values are the same, it is a horizontal line.
Now if ur x values would have been the same, u would have had a vertical line