NCERT Class 9 Mathematics Textbook for Blind and Visually Impaired Students made Screen Readable by Professor T K bansal.

In earlier classes, we studied algebraic expressions, their addition, subtraction, multiplication and division. We also studied how to factorise some algebraic expressions. We may recall the algebraic identities :

\[(x\ +\ y)^2\ =\ x^2\ +\ 2xy\ +\ y^2\]

\[(x\ −\ y)^2\ =\ x^2\ −\ 2xy\ +\ y^2,\]

and

\[x^2\ −\ y^2\ =\ (x\ +\ y)\ ×\ (x\ −\ y).\]

and their use in factorization. In this chapter, we shall start our study with a particular type of algebraic expressions, called polynomials, and the terminology related to them. We shall also study the Remainder Theorem and Factor Theorem and their use in the factorization of polynomials. In addition to the above, we shall study some more algebraic identities and their use in factorization and in evaluating some given expressions.