I suppose that you should have given some pairs to choose from.
Anyway, I can tell you how to do it. Given a pair
, you have to substitute
and
to
and
respectively, and see if you get something true.
For example, the pair
satisfies the function, because the substitution yields
![7=4\cdot 1+3](https://img.qammunity.org/2021/formulas/mathematics/college/sbj48remecucd0q1ykf0k69kghrilnyyje.png)
which is true. On the other hand, the pair
doesn't satisfy the function, because
![3=4\cdot 19+3](https://img.qammunity.org/2021/formulas/mathematics/college/7plt30qqvvjq66x3ibhk1dwny6h27b72mg.png)
is clearly false.