Categorize the following expressions based on the number of terms.
a2b+2aab−7ab2=3a2b−7ab2
The expression has been reduced to 2 terms. Hence, it is a binomial.
6x3yz2+x3yz2=7x3yz2
It contains only one term. Hence, it is a monomial.
3s2+st+3t3
It contains three terms. Hence, it is a trinomial.