Question 117206
slope=(-9+9)/(1+6)
slope=(0/7)
slope=0 
now replace the line formula [Y=mX+b]
-9=0*-6+b
b=-9
SO THE EQUATION IS Y=-9.
{{{ graph( 300, 200, -6, 5, -10, 10, Y = -9) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, Y = -9).