Polynomials • Topic 4 of 4

Factorization of Polynomials Using Identities

What is Factorization?

Factorization (or factoring) is the process of writing a polynomial as a product of simpler polynomials (factors). It's the reverse of multiplication.

Key Algebraic Identities for Factorization:

IdentityFormulaExample
**Perfect Square (Difference)**(x - y)² = x² - 2xy + y²(x - 5)² = x² - 10x + 25
**Difference of Squares**x² - y² = (x + y)(x - y)x² - 16 = (x + 4)(x - 4)
**Product of Binomials**(x + a)(x + b) = x² + (a + b)x + ab(x + 3)(x + 4) = x² + 7x + 12

Steps to Factor a Quadratic Trinomial (x² + bx + c):

  1. Find two numbers whose product = c and sum = b
  2. Write as (x + m)(x + n) where m × n = c and m + n = b

Special Cases:

  • If a ≠ 1 in ax² + bx + c, factoring requires more steps (splitting middle term)
  • Difference of squares: a² - b² = (a - b)(a + b)
  • Sum of squares a² + b² cannot be factored with real numbers
Factor Theorem & FactorisationFactor Theorem: (x - a) is a factor of p(x) ⟺ p(a) = 0i.e. a is a zero (root) of the polynomialFactorise: p(x) = x³ - 6x² + 11x - 6Try x=1: p(1) = 1 - 6 + 11 - 6 = 0 ✓ → (x-1) is a factorDivide: x³-6x²+11x-6 ÷ (x-1) = x²-5x+6Factorise x²-5x+6 = (x-2)(x-3)∴ p(x) = (x-1)(x-2)(x-3)Zeros of the polynomial: x = 1, 2, 3x=1x=2x=3
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Worked Example

Solve a standard problem on Factorization of Polynomials Using Identities.

Solution

Apply the formula/method shown in the concept section above.

Key Points

  • Understand the definition and properties of Factorization of Polynomials Using Identities.
  • Study the worked examples and practice similar problems.
  • Always verify your answer using the original conditions.
Tap an option to check your answer0 / 4
Q1.$a^2-b^2=$
Explanation: Difference of squares.
Q2.$a^2+2ab+b^2=$
Explanation: Perfect square.
Q3.$a^3+b^3=$
Explanation: Sum of cubes.
Q4.$x^2+5x+6=$
Explanation: Factor pair $2,3$.