Final answer:
The equation for the line in slope-intercept form is y = 3x + 9.
Step-by-step explanation:
In slope-intercept form, the equation for a line is written as y = mx + b, where m is the slope and b is the y-intercept.
m represents the rate at which y changes with respect to x, while b represents the y-coordinate of the point where the line intersects the y-axis.
Based on the given information, the equation for the line in slope-intercept form is y = 3x + 9. The slope is 3, indicating that for every increase of 1 on the horizontal axis, there is a rise of 3 on the vertical axis. The y-intercept is 9, meaning the line intersects the y-axis at the point (0, 9).