Final answer:
The equation of the line in slope-intercept form is y = 3x + 9, where the slope (m) is 3 and the y-intercept (b) is 9.
Step-by-step explanation:
The student is asked to write the equation of a line in slope-intercept form, which is represented as y = mx + b.
Given that the line has a y-intercept of 9 and a slope (m) of 3, the equation of the line can be determined. The y-intercept (b) is the point where the line intersects the y-axis, which in this case is 9. The slope indicates a rise of 3 units on the y-axis for every increase of 1 unit on the x-axis.
Inserting these values into the slope-intercept form gives us: y = 3x + 9.
This equation reflects the relationship between the x and y values for all points on the line.