(x+y)^2 Formula

3 min read Jun 17, 2024
(x+y)^2 Formula

Understanding the (x + y)² Formula

The formula (x + y)² is a fundamental concept in algebra, representing the square of the sum of two variables, x and y. It is commonly referred to as the "square of a binomial" and is a key tool in simplifying expressions and solving equations.

The Formula

The formula itself is:

(x + y)² = x² + 2xy + y²

This means that squaring the sum of two variables is equal to the sum of the squares of each variable plus twice the product of the two variables.

Derivation

The formula can be derived using the distributive property of multiplication:

(x + y)² = (x + y)(x + y)

Expanding the right side:

= x(x + y) + y(x + y)

= x² + xy + xy + y²

= x² + 2xy + y²

Applications

The (x + y)² formula has numerous applications in various areas of mathematics, including:

  • Simplifying algebraic expressions: It allows you to quickly expand and simplify expressions involving squared binomials.
  • Solving quadratic equations: The formula can be used to factor quadratic equations and find their roots.
  • Geometry: It is used in calculating areas of squares and rectangles.
  • Calculus: The formula is used in finding derivatives and integrals of functions.

Examples

Let's look at some examples of how to apply the formula:

1. Simplify (2a + 3b)²

Using the formula, we have:

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

= 4a² + 12ab + 9b²

2. Factorize x² + 6x + 9

Notice that this expression resembles the form of the expanded (x + y)² formula. We can identify x = x and y = 3, as 2xy = 6x and y² = 9. Therefore, we can factorize the expression as:

x² + 6x + 9 = (x + 3)²

Conclusion

The (x + y)² formula is a powerful tool for simplifying expressions and solving equations. Understanding its derivation and applications is essential for success in algebra and other related fields. Mastering this formula will allow you to manipulate algebraic expressions with greater ease and proficiency.

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