How do you classify the polynomial as a monomial, binomial, trinomial or none of these: $9{{x}^{4}}-4$ ?

Hint: In this question we have been asked to classify the given expression $9{{x}^{4}}-4$ as monomial, binomial, trinomial or none. From the basic concepts we know that a monomial is an expression that has only one term which is the product of positive integer powers of variables.

Complete step by step solution:
Now considering from the question we have been asked to classify the given expression $9{{x}^{4}}-4$ as monomial, binomial, trinomial or none.
From the basic concepts we know that a monomial is an expression that has only one term which is the product of positive integer powers of variables. Similarly a binomial is the one having two terms in which each term is the product of positive integer powers of variables whereas a trinomial is the one having three terms in which each term is the product of positive integer powers of variables and so on.
Here in the given expression we have two terms $9{{x}^{4}}$ and $-4$ and these terms are in the form of products of positive integer powers of variables. Therefore we can conclude it as a binomial.

Note: Here in this question or in questions of this type we should be sure with our concepts for solving it accurately within a less span of time. Similarly we can classify any expression as monomial, binomial, trinomial and so on. The examples of monomials are $4x,5q$ and the trinomial is $4x+5q+2$ .