Find the equation of the linear relationship

in slope intercept form: y=-3x+170

In point slope form: y-50=-3(x-40)

Step-by-step explanation:

Choose coordinates from the graph to calculate slope.

(30,80) and (40,50) are on grid lines , so the values are clear.

Find the slope by finding the difference in x-values divided by the difference in y-values

50-80 = -30   = -30 is the rise      

40 - 30 = 10  is the run  Rise/Run = slope -30/10 = -3

the slope m is -3

To find the y intercept, substitute the y and x values from any given coordinate into the slope intercept form and solve for  b

y= mx + b    b is the y-intercept   m is the slope

80 = (-3)(30) + b

80 = -90 + b

80 + 90 = b

170 = b

170 = b  This is the y-intercept

Rewrite the equation using the values found for  m and b

y = -3x + 170