The addition property of 0 states that for any number being added to zero, the sum is the same number.
For instance,

and so on.
In our case, we have in the left hand side:

that is, the given equation is equivalent to

Now, we can move 5 to the right hand side as -5, then we have

This means that any value of x fulfil the given equation.
For instance, if x=3, we have

If x=13, we have

and so on.