๐Ÿ“ˆcollege algebra review

Perfect square trinomial

Written by the Fiveable Content Team โ€ข Last updated September 2025
Written by the Fiveable Content Team โ€ข Last updated September 2025

Definition

A perfect square trinomial is a quadratic expression that can be written as the square of a binomial. It takes the form $a^2 + 2ab + b^2 = (a + b)^2$ or $a^2 - 2ab + b^2 = (a - b)^2$.

5 Must Know Facts For Your Next Test

  1. Identifying a perfect square trinomial involves recognizing it matches either $(a+b)^2$ or $(a-b)^2$ forms.
  2. The middle term in a perfect square trinomial is always twice the product of the square roots of the first and last terms.
  3. Factoring perfect square trinomials simplifies solving quadratic equations and understanding polynomial identities.
  4. Completing the square technique often uses perfect square trinomials to solve quadratic equations.
  5. Perfect square trinomials are always positive or zero since they result from squaring binomials.

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