The expression "plus one" simply means to add 1 to whatever it is applied to.
If you are referring to the "+1" sometimes found in comments on forum posts and the like, it is a reference to buttons labelled with "+1" or similar text, used to vote for the post or indicate a positive opinion of the post.
Addendum:
It's also possible that this question refers to the phrase as used on invitations - where the invitation is for the recipient and their guest. It can be used when you wish to invite someone to a function and aren't sure of who they're currently seeing...
3x plus 2y - 3 is an expression. There can be no answer to one expression and one linear equation in two variables.
Is 9x plus 5=32 AN EXPRESSION
The expression you plus 3v is not a real expression. People can say Òyou plus me could go do something.Ó As a question or you plus
It is a numerical expression.
an expression
no one knows exactly
3x plus 2y - 3 is an expression. There can be no answer to one expression and one linear equation in two variables.
It is an expression that comes from my coworker.
That one, there!
N plus ninety-one
83x + 523 is an algebraic expression. Were this expression set to be equal to something, one could then solve this expression for x.
-3
eigthy one plus a number
One plus one equals is to two. This is a mathematical expression in a sentence.
Is 9x plus 5=32 AN EXPRESSION
The expression you plus 3v is not a real expression. People can say Òyou plus me could go do something.Ó As a question or you plus
It is a numerical expression.