(x-a)(x-b) Formula Class 8

3 min read Jun 17, 2024
(x-a)(x-b) Formula Class 8

Understanding the (x-a)(x-b) Formula

In mathematics, the (x-a)(x-b) formula is a fundamental tool used to simplify and solve algebraic expressions. It is a special case of the distributive property and helps us expand products of binomials. Let's explore this formula in detail:

The Formula:

The (x-a)(x-b) formula states that the product of two binomials of the form (x-a) and (x-b) is equal to:

(x-a)(x-b) = x² - (a+b)x + ab

Expanding the Formula:

To understand how this formula works, let's break it down step by step:

  1. Multiply the first terms: x * x = x²
  2. Multiply the outer terms: x * (-b) = -bx
  3. Multiply the inner terms: (-a) * x = -ax
  4. Multiply the last terms: (-a) * (-b) = ab
  5. Combine the middle terms: -bx - ax = -(a+b)x

By combining all these terms, we arrive at the final expression: x² - (a+b)x + ab

Example:

Let's apply the formula to a specific example:

(x-2)(x-5)

Using the formula:

  • a = 2, b = 5
  • x² - (2+5)x + 2*5
  • x² - 7x + 10

Therefore, (x-2)(x-5) expands to x² - 7x + 10.

Benefits of the Formula:

The (x-a)(x-b) formula provides several benefits:

  • Simplifies algebraic expressions: It allows us to expand products of binomials quickly and efficiently.
  • Facilitates factoring: It helps us factor quadratic expressions by recognizing the pattern.
  • Essential for solving equations: It is a fundamental tool used in solving quadratic equations.

Conclusion:

The (x-a)(x-b) formula is an essential tool for students in Class 8 and beyond. Understanding this formula and its applications will provide a solid foundation for further mathematical learning and problem-solving. Practice using the formula with various examples to master its application and solidify your understanding of algebraic manipulation.

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