The answer is 30 days until it appears on a Friday again. In order to see the full moon again, we have to go through the entire cycle. So, it will be about 30 days before we would have seen another one.
This would be any equation whose slope isn’t -1 or 1.
If the slope was -1, the lines would be parallel because the have the same slope.
If the slope was 1, the lines would be perpendicular because 1 is the negative reciprocal of -1.
Any line with any other slope will intersect with y=-x.
Hope this helps!
Answer: 4.12032 which is also equivalent to 4:12
I hope this helps answer your question.