Question

What does "Classify the polynomial by the number of terms" mean

Answer 1

"Classify the polynomial by the number of terms" means a term contains both the variables and its coefficient. For example a "monomial" has one term like $2x^{2}$.

A binomial has 2 terms like $3x^{2}+6x$

A trinomial has 3 terms like $4x^{2}+5x-8$

And a polynomial has 4 or more terms.

So basically one can classify the type of polynomial by counting the number of terms in a given equation.