Step-by-step explanation:
71.5
....................
The answer is -3 . Use the gradient formula y2-y1/x2-x1
There is infinitely many ratios which are equivalent to 5:9. As we know always we can write divide as fraction, so

. We can multiply nominator and denominator by the any number (but the same) and get another numbers but ratio will be the same, so equivalent.
For example
10:18,
15:27
I believe the answer would be Whole Numbers