(x-9)^2

3 min read Jun 17, 2024
(x-9)^2

Understanding (x-9)^2

(x-9)^2 is a mathematical expression that represents the square of the binomial (x-9). To understand this expression better, let's break down its components and explore its properties:

Binomial Expansion

The expression (x-9)^2 is essentially the product of (x-9) with itself:

(x-9)^2 = (x-9) * (x-9)

To expand this, we can use the FOIL method (First, Outer, Inner, Last):

  • First: x * x = x^2
  • Outer: x * -9 = -9x
  • Inner: -9 * x = -9x
  • Last: -9 * -9 = 81

Adding these terms together, we get the expanded form:

(x-9)^2 = x^2 - 9x - 9x + 81 = x^2 - 18x + 81

Properties of the Expression

  • Quadratic Equation: The expanded form of (x-9)^2 is a quadratic equation, which is a polynomial equation of the second degree.
  • Vertex Form: The expression can be rewritten in vertex form, which is a standard form for quadratic equations that reveals the vertex of the parabola:

(x-9)^2 = (x-9)^2 + 0

  • Vertex: The vertex of the parabola represented by the expression is at the point (9, 0).

Applications

The expression (x-9)^2 has various applications in mathematics and other fields, including:

  • Algebra: Solving quadratic equations and simplifying expressions involving binomials.
  • Calculus: Finding derivatives and integrals of functions involving binomials.
  • Geometry: Calculating areas and volumes of shapes derived from the expression.
  • Physics: Modeling physical phenomena that can be represented by quadratic functions.

Understanding the properties and expansion of (x-9)^2 is crucial for working with quadratic equations and various mathematical concepts.

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