Answer:
y=-3x-7
Step-by-step explanation:
The equation of a straight line is y=mx+b where m is the gradient (slope) and b is the y-intercept.
If two lines are parallel, that implies their gradient is the same (if it wasn't, then they'd cross at some point).
Therefore, we want the line with the same gradient for this question.
The gradient of our line is -3, so the line with the same gradient is y=-3x-7