This poster has helped my students a lot. It was easy to make on card stock. The white a, b and c is white out. That wasn't part of the original poster but it soon became apparent that I needed to emphasize which part of the formula needed values plugged in.
That slide above is part of the Powerpoint I shine on the smart board that goes along with the warm up template. Students transfer the equation onto their template and solve on their own.
You can get this Quadratic Formula template here. You can also check out this post for more free Algebra and Algebra 2 warm up templates.
If you're looking for a way to summarize your unit, this Quadratic Formula pennant is a fun way to assess student understanding of the Quadratic Formula while also decorating your classroom with math.