To determine the equation of the trend line in slope-intercept form (y = mx + b), we first need to find the slope (m) and the y-intercept (b).
From the points mentioned:
- (0, 9)
- (4, 8)
- (8, 7)
- (10, 6.5)
Let's calculate the slope (m) using two points, for example, (0, 9) and (10, 6.5):
\[ m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{6.5 - 9}{10 - 0} = \frac{-2.5}{10} = -0.25 \]
Next, we use the slope-intercept form and the y-intercept from the point (0, 9). Since the line passes through (0, 9), the y-intercept (b) is 9.
Putting it all together, we have:
\[ y = -\frac{1}{4}x + 9 \]
Therefore, the correct answer is:
y = −1/4x + 9.