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Algebraic Expressions

• A variable is something that does not have a fixed value. The value of a variable varies.
• Variables are represented by English letters such as x, y, z, a, b, c etc.
• A combination of variables, numbers and operators (+, –, × and ÷) is known as expression.
• Using different operations on variables and numbers, expressions such as , can be formed.

Example:

Meena’s age is 4 years less than 7 times the age of Ravi. Express it using variables.

Solution:

Let the age of Ravi be x years.

7 times the age of Ravi can be expressed as 7x.

4 years less than 7 times the age of Ravi can be written as 7x – 4.

∴ Age of Meena = (7x – 4)

• Algebraic expressions are formed by combining variables with constants using operations of addition, subtraction, multiplication and division.

For example: 4xy, 2x2 – 3, 7xy + 2x, etc.

In an algebraic expression, say 2xy – 3x2 + 2; 2xy, (–3x2), 2 are known as the terms of the expression.

The expression 2xy – 3x2 +2 is formed by adding the terms 2xy, (–3x2) and 2 where 2, x, y are factors of the term 2xy; (–3), x, x are factors of the term (–3x2); 2 is the factor of the term 2.

For an expression, the terms and its factors can…

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