Final answer:
The parallel line will have the same slope as the given line, which is 3. Using the x-intercept of -3, we find the y-intercept to be 9. Thus, the equation of the parallel line is y = 3x + 9.
Step-by-step explanation:
The question asks for the equation of a line that is parallel to a given line and that has an x-intercept of -3. A line parallel to another will have the same slope. The given line, with the equation y = 9 + 3x, has a slope of 3. Hence, the parallel line must also have a slope of 3. Next, we determine the y-intercept of the parallel line by using its known x-intercept, which is -3. When the line crosses the x-axis, the y-coordinate is 0. So we plug these values into the slope-intercept form equation, y = mx + b, where m is the slope and b is the y-intercept:
0 = 3(-3) + b
0 = -9 + b
b = 9
Thus, the equation of the parallel line is y = 3x + 9, which is not listed in the answer choices. However, there might be a typo in the provided answer choices or in the question. The parallel line matches the description of the given line, suggesting the question intended to inquire about a line parallel to another not described here