Algebra
Basic

Perfect Square Trinomial

Expands the square of a binomial.

Formula

(a±b)2=a2±2ab+b2(a \pm b)^2 = a^2 \pm 2ab + b^2

Variables

a, bAny real numbers

Example

(x+3)² = x² + 6x + 9

Did You Know?

Recognizing perfect-square trinomials is the key step in "completing the square", which derives the quadratic formula itself.

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