[] One solution
-> x = 2 + 3
-> 2 + 3 can only equal one thing, 5.
[] Invitinte solutions
-> 3x - 6y = 9
-> This is a linear equation, so it will go on forever. If you graph it you can find the solutions.
-> See attached
Have a nice day!
I hope this is what you are looking for, but if not - comment! I will edit and update my answer accordingly.
- Heather