Math Problem Statement

Factorise the quadratic expressions: (a) x^2 - 4, (b) 3x^2 - 11x - 4, (c) 3x^2 + 4x - 4

Solution

Let's solve each part of the factorization step-by-step:

(a) Factorize x24x^2 - 4

This is a difference of squares: x24=(x2)(x+2)x^2 - 4 = (x - 2)(x + 2)

(b) Factorize 3x211x43x^2 - 11x - 4

For this quadratic, we will use factoring by splitting the middle term. We need to find two numbers that multiply to 3×(4)=123 \times (-4) = -12 and add up to 11-11. The numbers are 12-12 and 11.

Now, split the middle term: 3x212x+x43x^2 - 12x + x - 4 Factor by grouping: 3x(x4)+1(x4)3x(x - 4) + 1(x - 4) Factor out the common binomial: (3x+1)(x4)(3x + 1)(x - 4)

(c) Factorize 3x2+4x43x^2 + 4x - 4

For this quadratic, we again factor by splitting the middle term. We need to find two numbers that multiply to 3×(4)=123 \times (-4) = -12 and add to 44. The numbers are 66 and 2-2.

Now, split the middle term: 3x2+6x2x43x^2 + 6x - 2x - 4 Factor by grouping: 3x(x+2)2(x+2)3x(x + 2) - 2(x + 2) Factor out the common binomial: (3x2)(x+2)(3x - 2)(x + 2)

Final answers:

  • (a) (x2)(x+2)(x - 2)(x + 2)
  • (b) (3x+1)(x4)(3x + 1)(x - 4)
  • (c) (3x2)(x+2)(3x - 2)(x + 2)

These factorizations match the options in the image.

Would you like more details, or do you have any questions?

Here are five related questions to deepen your understanding:

  1. What is the difference of squares, and when can it be applied?
  2. How do you determine which method to use when factoring quadratics?
  3. Can every quadratic expression be factored, or are there exceptions?
  4. How does the discriminant of a quadratic equation affect its factorization?
  5. Why is grouping used when factoring quadratics with a leading coefficient greater than 1?

Tip: Always check your factored expression by expanding it back to ensure correctness.

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Math Problem Analysis

Mathematical Concepts

Algebra
Factorization
Quadratic Equations

Formulas

Difference of squares: a^2 - b^2 = (a - b)(a + b)
Factoring by grouping for quadratics: ax^2 + bx + c

Theorems

Difference of squares theorem
Factoring quadratics theorem

Suitable Grade Level

Grades 8-10