Question

For which equation is x= 5 a solution.

Answer 1

There are many equations that could prove this. Some include x=5, x-1 =4, x=4+1, etc...

Answer 2

Do have a list of equations in particular. I don't see it. But if you want to know if x=5 is a solution plug in the x value into the equation to see what the answer is. If the answer given matches your answer you are right.