slope intercept form is just a fancy way of saying y=mx+b
x being your input, y your output, m your slope, and b your y intercept
you can use the slope to determine your equation will look something like: y=-2/7x+b. To find your y-intercept all you do is determine how much the point will increase or decrease so it is equal to (0, y). In this case it will increase by 14 on the x's (so x is equal to 0) and 14*-2/7. When you have determined your y-int and slope you can then plug them into the equation instead of the variables.
