Learn Class 8 Math - Algebraic Expressions and Identities

Algebraic expressions are made from variables and constants in conjunction with mathematical operators. These expressions don't have any facets or signals like algebraic equations. Example – 4x²+3x-6, 7x+1, etc.

Some basic terminology :

• Factors - This means all the possible parts of the product. One is a basic factor for everything. Example- factors of 7x are 1,7,x, and 7x.
• Terms - A variable or constant, or a constant multiplied by a variable, is Known as a term. Example -4y, 7, 9x.
• Coefficients - Formation of the term when a constant is multiplied by variable/variables; that constant is Known as coefficients. Example – 6x, here 6 is the coefficient.

Some basic terminology :

There are three types of expressions in Algebra:

• Monomial Expression - An expression that includes only one term is Known as Monomial Expression. For example - 10x, 6y.
• Binomial Expression - An expression with two different or unlike terms is known as Binomial Expression. For example- 70xy+10
• Polynomial Expression - An expression that consists of more than one term with non-negative integer exponents is known as Polynomial Expression. For example – 4x+6y+8z.

Algebraic Identities

When equality holds true for all then it is understood as Identities. There are 4 Identities:

(x+y)² = x²+y²+2xy

(x-y)² = x²+y²-2xy

(x+y)(x-y) = x²-y²

(x+y+z)² = x²+y²+z²+2xy+2yz+2zx