Chapter 3 · Class 9 ICSE · Formula Sheet

Expansions Formulas — Class 9 ICSE

Use standard algebraic identities to expand expressions and simplify complex products.

Key Formulas

Identity 1

(a + b)^2 = a^2 + 2ab + b^2

Identity 2

(a - b)^2 = a^2 - 2ab + b^2

Identity 3

(a + b)(a - b) = a^2 - b^2

Three Variable

(a + b + c)^2 = a^2 + b^2 + c^2 + 2ab + 2bc + 2ca

Cube of Sum

(a + b)^3 = a^3 + 3a^2b + 3ab^2 + b^3

Cube of Difference

(a - b)^3 = a^3 - 3a^2b + 3ab^2 - b^3

Sum of Cubes

a^3 + b^3 = (a+b)(a^2 - ab + b^2)

Difference of Cubes

a^3 - b^3 = (a-b)(a^2 + ab + b^2)

Worked Examples

1Using: Application

Apply the key formula from this topic to a sample problem.

Step 1: Identify the formula.

Step 2: Substitute the values.

Step 3: Simplify to get the answer.

Answer: See solution above

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More Class 9 ICSE Formulas

Rational & Irrational NumbersCompound InterestFactorizationSimultaneous Linear EquationsIndices (Exponents)Logarithms

Frequently Asked Questions

How many formulas are in Class 9 ICSE Expansions?+
There are 8 formulas in the Expansions chapter for Class 9 ICSE. Each formula is essential for solving problems in this topic.
How to remember Expansions formulas easily?+
Practice regularly with worked examples, group related formulas together, and use SparkEd's interactive practice mode to reinforce your memory through problem-solving.
Are these Expansions formulas enough for exams?+
Yes, these formulas cover the complete ICSE Class 9 syllabus for Expansions. Practice applying them to different types of questions for full exam readiness.

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