Since the trend line passes through the points (0, 30), (15, 40), and (30, 50), we can calculate the slope using the formula (y2 - y1) / (x2 - x1).
Slope = (50 - 30) / (30 - 0) = 20 / 30 = 2/3
Next, we know the trend line intersects the y-axis at 30, which is the y-intercept.
Therefore, the equation of the trend line in slope-intercept form is:
y = (2/3)x + 30
So, the correct answer is:
y equals Start Fraction 2 over 3 End Fraction x plus 30