Is 2x + 5 is an equation or expression? Please advise.?

expression

an equation would be something like 2x + 5 =3 and it can be solved to give a value for x

it's an expression because 2x + 5 doesn't equal anything

It is an expression because it has no "equal sign".

An equation requires an = sign.
What we have here is an expression.

expression.
to help you remember:
equ- is the same beginning in equal and equation. you need an equal sign to make in an equation. an expression doesn't have an equal sign.