Answer: 3x+y = -4
Step-by-step explanation:
Anything parallel to Ax+By = C is of the form Ax+By = D, where C and D are different values.
The given equation is 3x+y = 3. Anything parallel to this is 3x+y = D
Plug (x,y) = (1,-7) into that second equation to compute D
3x+y = D
D = 3x+y
D = 3(1)+(-7)
D = 3-7
D = -4
Therefore, our answer is 3x+y = -4
If you wanted to solve for y, then you'd get y = -3x-4. Both parallel lines have a slope of -3 but different y intercepts.