Chapter 8 — Algebraic Expressions and Identities

Chapter 8 of Class 8 Mathematics, "Algebraic Expressions and Identities," teaches how to add, subtract, and multiply algebraic expressions including monomials, binomials, trinomials, and polynomials using the distributive law and rules of exponents.

This chapter covers the fundamental operations on algebraic expressions. Students learn to add and subtract expressions by combining like terms, multiply monomials by monomials and by polynomials using the distributive property, and multiply polynomials by binomials and trinomials. The chapter includes practical applications such as finding the area of rectangles, volumes of boxes, and pricing problems, with systematic step-by-step methods for each operation type.

1. 01Like terms have the same variables with the same powers; add or subtract them by combining coefficients
2. 02Monomial: expression with exactly one term; multiply two monomials by multiplying coefficients and combining variable powers using exponent rules
3. 03Distributive law: multiply a monomial by a polynomial by distributing the monomial to each term in the polynomial
4. 04Binomial × binomial: each term in one binomial multiplies each term in the other; combine like terms in the result
5. 05Binomial × trinomial produces 6 terms initially (2 × 3) that may reduce when like terms are combined
6. 06All algebraic operations (addition, subtraction, multiplication) follow the same laws as number operations (commutative, associative, distributive)
7. 07Real-world applications: area of rectangle = length × breadth, volume of box = length × breadth × height, cost = price × quantity