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The part of mathematics in which letters and other general symbols are used to represent numbers and quantities in
formulae and equations.

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Term: A word or phrase used to describe a thing or to express a concept
Expression: It is a mathematical sentence; it doesn't have an equal sign
Equation: It is a complete Mathematical sentence that includes a sign of equality

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• VARIABLE
A variable is a symbol which represents a quantity that can vary.
• CONSTANT
A constant is a symbol which represents a specific number (a quantity does not vary).
• COEFFICIENT
The number that is multiplied by the variable.

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The general arithmetic operations performed in the case of algebra are:

Addition: x + y

Subtraction: x – y

Multiplication: xy

Division: x/y or x ÷ y

where x and y are the variables.

The order of these operations will follow the BODMAS rule, which means the terms inside the brackets are considered first. Then, roots and exponents are operated on second priority. Solve all the division and multiplication operations and later addition and subtraction.

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The general formulas used in algebra to solve algebraic equations and find the values of unknown variables are given here:

a2 – b2 = (a – b)(a + b)

(a+b)2 = a2 + 2ab + b2

a2 + b2 = (a – b)2 + 2ab

(a – b)2 = a2 – 2ab + b2

(a + b + c)2 = a2 + b2 + c2 + 2ab + 2ac + 2bc

(a – b – c)2 = a2 + b2 + c2 – 2ab – 2ac + 2bc

(a + b)3 = a3 + 3a2b + 3ab2 + b3

(a – b)3 = a3 – 3a2b + 3ab2 – b3

These fomulas are used in higher secondary classes. Students can find algebra formulas for class 8, along with class 9, class 10, class 11 and class 12 here.

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•Find y, when, y + 15 = 30

Solution: y = 30 – 15

y = 15

•Find x, when, 9x = 63

Solution:x = 63/9

x = 7

•If x/7 = 21, then find x.

Solution: Given x/7 = 21

or x = 21 x 7

x = 147

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Example 1: Find the value of x in the following equation using the Algebra concepts. 3x + 4 = 28

Solution:

3x + 4 = 28

3x = 28 - 4

3x = 24

x = 8

Therefore, the value of x = 8

Example 2: Five less than a number equals to two. What is the number?

Solution:

Using the concepts of Algebra, we will assume the number to be a variable. Let the number be x. As per the question, we can write x - 5 = 2. On solving this, we get x = 7. Therefore, the required number is 7.

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In the primary curriculum algebra can be seen as the development of children's ability to think and reason logically
and systematically.