State whether each expression is a polynomial. If the expression is a polynomials, identify it as a monomial,a binomial, or a trinomials.

1.7a^2b+3b^2-a^2b
2.1/5y^3+y^2-9
3.6g^2h^3k

Are these the right answers?
1.Yes-trinomials
2.No
3.Yes- monomials.