To find the equation of the trend line in slope-intercept form (y = mx + b), we need to determine the slope (m) and the y-intercept (b) using the points on the line.
From the points mentioned:
- (0, 8)
- (10, 6)
- (15, 5)
- (20, 4)
- (25, 3)
- (40, 0)
Step 1: Calculate the slope (m)
Using the points (0, 8) and (10, 6):
\[ m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{6 - 8}{10 - 0} = \frac{-2}{10} = -\frac{1}{5} \]
Step 2: Find the y-intercept (b)
From the point (0, 8), we see that when x = 0, y = 8. Therefore, the y-intercept (b) is 8.
Step 3: Write the equation
Now, we can write the equation of the trend line:
\[ y = -\frac{1}{5}x + 8 \]
Thus, the correct answer is:
y equals negative Start Fraction 1 over 5 End Fraction x plus 8.