__CHAPTER 9 ALGEBRAIC EXPRESSIONS AND IDENTITIES__- Expressions are formed from variables and constants.

- An expression is made up of terms and terms are made up as product of factors.

- Types of expressions:
- Monomials: Containing one term
- Binomials: Containing two terms
- Trinomials: Containing three terms
- Polynomials: Any expression with one or more terms with non-zero coefficients

- While adding or subtracting polynomials, operate on the like terms and then move on to the unlike terms.

- An identity is an equality which is true for all values of the variables in the equality.