Points and crossings

You will write a function that tests whether a point is on a line, another for a pair, and use them to search for the solution of a pair.

The idea. A point $(p, q)$ is on the line $ax + by + c = 0$ when $a \times p + b \times q + c = 0$. It is a solution of a pair when it is on both lines.

Your tasks.

1. In on_line, return True when the point is on the line $ax + by + c = 0$.
2. In is_solution, return True when the point is on both lines of the pair.
3. Set found to the points $(x, y)$ with $x$ and $y$ whole numbers from $0$ to $10$ that are solutions of pair.