y=mx+b where m=-6, x=-2, and y=-3. Substituting these values in would result in -3=(-6)(-2)+b, which would simplify to -3=12+b, and further to b=-15. This would mean the y intercept is equal to -15, or (0,-15). To check, (-6)*(-2)-15 is in fact equal to -3, thus allowing easy identification of a graph, which will cross the y axis at -15 and decrease in y-value by 6 with every increase in x-value.
