What is Factorisation Class 8: Definition and Easy Methods Explained
By ConceptScroll Team · Published on 19 June 2026 · 3 min read
What is Factorisation Class 8? Factorisation is the process of breaking down an algebraic expression into simpler factors that, when multiplied, give the original expression. This concept is crucial in the NCERT Class 8 Mathematics syllabus and helps solve equations efficiently.
Understanding Factorisation: Definition and Importance
Factorisation means expressing a number or algebraic expression as a product of its factors. In Class 8 Mathematics, it helps simplify expressions and solve equations easily.
- It breaks down complex expressions into simpler parts.
- Makes algebraic manipulation easier.
- Essential for solving quadratic and higher-degree polynomials.
For example, factorising $x^2 - 9$ gives $(x - 3)(x + 3)$, which is easier to work with in equations.
Common Methods of Factorisation in Class 8
Class 8 NCERT covers several factorisation methods:
- Taking Common Factors: Extract the greatest common factor (GCF) from terms.
- Factorisation by Grouping: Group terms to find common factors.
- Using Algebraic Identities: Apply formulas like $a^2 - b^2 = (a - b)(a + b)$.
- Factorising Quadratic Trinomials: Express $ax^2 + bx + c$ as a product of two binomials.
Example: Taking Common Factor
Factorise $6x^3 + 9x^2$:
- GCF is $3x^2$.
- Expression becomes $3x^2(2x + 3)$.
This method simplifies expressions quickly.
Want to test yourself on Factorisation? Try our free quiz →
Step-by-Step Guide to Factorising Algebraic Expressions
Follow these steps to factorise:
1. Look for a common factor in all terms. 2. Apply algebraic identities if applicable. 3. Use grouping for four-term expressions. 4. Check your factors by multiplying back.
Worked Example:
Factorise $x^2 + 5x + 6$:
- Find two numbers that multiply to 6 and add to 5: 2 and 3.
- Rewrite as $x^2 + 2x + 3x + 6$.
- Group: $(x^2 + 2x) + (3x + 6)$.
- Factor each group: $x(x + 2) + 3(x + 2)$.
- Take common factor $(x + 2)$: $(x + 2)(x + 3)$.
This shows how to factor quadratic trinomials.
Comparing Factorisation Methods: When to Use Which?
Different expressions require different methods. Here's a comparison:
| Expression Type | Best Method | Example |
|---|---|---|
| Terms with common factors | Taking Common Factor | $4x + 8$ → $4(x + 2)$ |
| Four-term expressions | Factorisation by Grouping | $ax + ay + bx + by$ |
| Difference of squares | Algebraic Identity | $x^2 - 16$ → $(x - 4)(x + 4)$ |
| Quadratic trinomials | Splitting middle term | $x^2 + 7x + 10$ |
Choose the method based on the expression structure for efficient factorisation.
Why Factorisation is Important in Class 8 NCERT Maths
Factorisation is a foundational skill in Class 8 NCERT Mathematics because:
- It simplifies solving equations and inequalities.
- Helps in understanding polynomial expressions better.
- Prepares students for higher classes where factorisation is used extensively.
- Enhances problem-solving skills in algebra.
Mastering factorisation improves your ability to tackle complex problems in exams and builds a strong math foundation.
Frequently asked questions
What is factorisation in Class 8 Maths?
Factorisation is breaking an expression into simpler factors that multiply to the original expression.
How do you factorise a quadratic expression?
Find two numbers that multiply to the constant term and add to the middle term, then split and group.
What is the difference between factorisation and expansion?
Factorisation breaks expressions into factors; expansion multiplies factors to form an expression.
Why is factorisation important for Class 8 students?
It simplifies solving algebraic problems and is key for higher-level math concepts.
Can all algebraic expressions be factorised?
Not all expressions can be factorised easily; some are prime or require advanced methods.
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