Perfect Square Trinomials



When a perfect square trinomial is written in the form \(ax^2 + bx + c\), and \(a = 1\), the following patterns emerge, as seen in the Investigation.

  • \(c\) is always the square of one-half of the coefficient of the middle term, or \(c = \left( {\frac{b}{2}} \right)^2 \).

  • The factors are always in the form \(\left( {x + \frac{b}{2}} \right)\left( {x + \frac{b}{2}} \right) = \left( {x + \frac{b}{2}} \right)^2 \).




 Key Lesson Marker

Perfect Square Trinomials


In general, a perfect square trinomial with \(a = 1\) is

\(ax^2 + bx + c = x^2 + 2rx + r^2 = \left( {x + r} \right)^2 \), where \(r = \frac{b}{2}\)