Perfect Square Trinomial

Definition

A perfect square trinomial is a polynomial expression of the form $a^2 + 2ab + b^2$, where $a$ and $b$ are real numbers. This type of trinomial can be factored into a single binomial squared, such as $(a + b)^2$.

5 Must Know Facts For Your Next Test

1. Perfect square trinomials are a special case of trinomials that can be easily factored.
2. The general form of a perfect square trinomial is $a^2 + 2ab + b^2$, where $a$ and $b$ are real numbers.
3. Factoring a perfect square trinomial involves finding the square of a binomial, such as $(a + b)^2$.
4. Perfect square trinomials are often encountered when solving quadratic equations using the square root property or completing the square.
5. Recognizing and factoring perfect square trinomials is an important skill for simplifying algebraic expressions and solving quadratic equations.

Review Questions

• Explain how perfect square trinomials are related to the topic of factoring trinomials of the form $x^2 + bx + c$.
  • Perfect square trinomials are a special case of trinomials of the form $x^2 + bx + c$, where $b = 2a$ and $c = a^2$. This means that a trinomial of the form $x^2 + 2ax + a^2$ can be factored as a perfect square, $(x + a)^2$. Recognizing and factoring perfect square trinomials is an important skill in the broader context of factoring general trinomials.
• Describe how perfect square trinomials are used in the process of solving quadratic equations by completing the square.
  • When solving quadratic equations of the form $ax^2 + bx + c = 0$ using the method of completing the square, the goal is to rearrange the equation into the form $(x - h)^2 = k$, where $h$ and $k$ are constants. This can be achieved by identifying the perfect square trinomial within the original equation, which will have the form $a^2 + 2ab + b^2$, where $a$ and $b$ are appropriately chosen constants. Factoring this perfect square trinomial is a crucial step in the completion of the square process for solving quadratic equations.
• Analyze the relationship between perfect square trinomials and the square root property used to solve quadratic equations.
  • The square root property for solving quadratic equations states that if $x^2 = a$, then $x = \pm \sqrt{a}$. This property is particularly useful when the quadratic equation can be rearranged into the form of a perfect square trinomial, $a^2 + 2ab + b^2$. In this case, the equation can be factored as $(a + b)^2 = c$, allowing the solution to be found by taking the square root of both sides, $x = \pm (a + b)$. The recognition and factorization of perfect square trinomials, therefore, plays a vital role in the application of the square root property for solving quadratic equations.

Related terms

Trinomial:

A polynomial expression with three terms, typically in the form $ax^2 + bx + c$, where $a$, $b$, and $c$ are real numbers.

Factoring:

The process of expressing a polynomial as the product of two or more smaller polynomials.

Completing the Square:

A method used to solve quadratic equations by rearranging the equation to the form $(x - h)^2 = k$, where $h$ and $k$ are constants.