(-a+b-c)^2 Formula

3 min read Jun 16, 2024
(-a+b-c)^2 Formula

Squaring a Trinomial: The (-a + b - c)^2 Formula

The formula (-a + b - c)^2 is a specific case of squaring a trinomial. Understanding this formula can help you simplify expressions and solve equations more efficiently.

The Formula:

The formula for (-a + b - c)^2 is:

(-a + b - c)^2 = a^2 + b^2 + c^2 - 2ab + 2ac - 2bc

Understanding the Formula:

This formula is derived using the distributive property of multiplication. Here's a breakdown of how it works:

  1. Expansion: The expression (-a + b - c)^2 means multiplying the trinomial by itself: (-a + b - c) * (-a + b - c)

  2. FOIL Method: We can use the FOIL method (First, Outer, Inner, Last) to expand the multiplication:

    • First: (-a) * (-a) = a^2

    • Outer: (-a) * (b) = -ab

    • Inner: (b) * (-a) = -ab

    • Last: (b) * (b) = b^2

    • First: (-a) * (-c) = ac

    • Outer: (b) * (-c) = -bc

    • Inner: (-c) * (-a) = ac

    • Last: (-c) * (b) = -bc

  3. Combining Terms: Adding all the terms together, we get:

    • a^2 + b^2 + c^2 - 2ab + 2ac - 2bc

Application:

This formula is useful in many areas of mathematics, including:

  • Algebraic Simplification: It allows you to simplify complex expressions involving trinomials.
  • Equation Solving: It can be used to solve equations where the variable is squared, such as quadratic equations.
  • Geometry: The formula can be applied to find the area of certain geometric shapes.

Example:

Let's say we want to simplify the expression (2x - 3y + 1)^2:

  1. We can apply the formula:

    • (2x - 3y + 1)^2 = (2x)^2 + (-3y)^2 + (1)^2 - 2(2x)(-3y) + 2(2x)(1) - 2(-3y)(1)
  2. Simplify:

    • = 4x^2 + 9y^2 + 1 + 12xy + 4x + 6y

Conclusion:

The formula (-a + b - c)^2 = a^2 + b^2 + c^2 - 2ab + 2ac - 2bc is a valuable tool for simplifying expressions and solving problems in various mathematical contexts. By understanding its derivation and applications, you can gain a deeper understanding of algebraic manipulations.