EXPLANATION
Binomial is a polynomial with two, unlike terms while a trinomial is an algebraic expression (polynomial) with three, unlike terms.
From the question given:
[tex]a^3b+9a^2b^2-4ab^5-(a^3b-3a^2b^2+ab^5)[/tex]
Simplify the above by first opening the parenthesis.
[tex]a^3b+9a^2b^2-4ab^5-a^3b+3a^2b^2-ab^5[/tex]
Add/ subtract the like terms.
[tex]=11a^2b^2-5ab^5[/tex]
Since, there are only 2 terms in the result, then it is a binomial.
Also, the highest exponent in the expression is the degree of the binomial.
The highest component in this case is 6, hence it is of degree 6 when the exponent of a and b are added.
Therefore, it is a binomial with degree 6.
