# How do you determine if 21 is a polynomial and if so, how do you identify if it is a monomial, binomial, or trinomial?

Jun 7, 2017

Look for the number of terms that are separated by + or - signs.

#### Explanation:

If 21 would written as $2 \times 10 + 1 \times 1$ it would be clear that the number is a binomial. The plus sign between the tens and the ones gives it away. So technically 21 is a binomial but for practical purposes it can be regarded as monomial as the two terms can be combined.

A monomial has only one term. Everything can be combine without a plus or a minus sign. such as 4x ( 4 xx x)

A binomial has two terms. There are unlike terms that cannot be combined. such as x + 4 there is one plus or minus sign.

A trinomial has three terms. There are three unlike terms that can not be combines such ${x}^{2} + 4 x + 4$ there are two plus or minus signs.