The equation for slope intercept would be y=mx+b. b is the y intercept, and Since the line intersects the y-axis at -4, b is equal to -4. The slope (m) is rise over run, so it equals -4/2. That simplifies to -2. It comes from the amount of units it goes up, and the amount of units it goes left or right. If it goes left it is negative. So overall the equation is y=-2x-4
