Answer: 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
