Question

What is the difference between algebraic expression and polynomial

Answer 1

"Polynomial" is a precisely defined term. A polynomial is constructed from constants and variables by adding and multiplying. One could add "subtracting", but x−y is x+(−1)y, so adding and multiplying are enough.

"Alebraic expression" is not a precisely defined term. Algebraic expressions include many things that are not polynomials, including rational funtions, which come from dividing polynomials, and things like √x.