# Does "Show by insertion" make sense mathematically?

In math classes you might be given an equation like

2+x=5

and a valute like x=3. In my native Danish tongue I could now say one of the following:

Vis ved indsættelse, at x=3 er en løsning.

Vis ved at gøre prøve, at x=3 er en løsning.

These directly translate to:

Show by insertion that x=3 is a solution.

Show by testing that x=3 is a solution.

Are this direct/literal translations correct? Is "show by insertion" meaningful for this purpose? Obviously the point is that the given value should be input in place of the x in the equation, but is this phrase how an English speaker would refer to such an action?

You can use the verb substitute.

An example is on this basic math page math is fun:

Substitution
In Algebra "Substitution" means putting numbers where the letters are:
When we have: x − 2
And we know that x = 6 ...
then we can "substitute" 6 for x:
6 − 2 = 4

So the translation is (in your example)

Show by substitution that x=3 is a solution.