Final answer:
The equation of the linear function is y = 3x + 9.
Step-by-step explanation:
The equation of the linear function can be determined by using the slope-intercept form, which is y = mx + b, where m represents the slope and b represents the y-intercept. From the given graph, we can observe that the y-intercept is 9 and the slope is 3. Therefore, the equation of the linear function is y = 3x + 9.