RBSE Class 8 Maths Notes Chapter 9 Algebraic Expressions and Identities

These comprehensive RBSE Class 8 Maths Notes Chapter 9 Algebraic Expressions and Identities will give a brief overview of all the concepts.

RBSE Class 8 Maths Chapter 9 Notes Algebraic Expressions and Identities

→ An algebraic expression is a combination of variables and constants.

→ Terms are added to form expressions. Terms themselves are formed as product of factors.

→ An expression having only one term is called monomial.

→ An expression having two terms is called binomial.

→ An expression having three terms is called trinomial.

→ In general, any expression containing one or more terms with non-zero coefficients (and with variables having non-negative exponents) is called polynomial.

→ Like terms are formed from the same variables and the powers of these variables are the same, too. Coefficients of like terms need not be the same.

→ While adding (or subtracting) polynomials, first look for like terms and add (or subtract) them; then handle the unlike terms.

→ A monomial multiplied by a monomial always gives a monomial.

→ While multiplying a polynomial by a monomial, we multiply every term in the polynomial by the monomial.

→ In carrying out the multiplication of a polynomial by a binomial (or trinomial), we multiply term by term.

→ An Idetftity is an equality, which is true for all values of the variables in the equality. But an equation is tme only for certain values of its variables. An equation is not an identity.

→ Some important identities:

• (a + b)² = a² + 2ab + b²
• (a - b)² = a² - 2ab + b²
• (a + b) (a - b) = a² - b²
• (x + a) (x + b) = x² + (a + b) x + ab