Grand Rapids, MI
Here’s what you should know about the corner of Bostwick and Crescent in downtown GR: I had my first algebra class in a building on that corner. On the third floor, I had Algebra 1 with Mrs. Molloy. I am sure that was the first time I spent any quality time with the quadratic formula.
The building where I went to middle and high school is no longer standing. Luckily, it was replaced with the science building of the local community college. I think someone going to or from that building will appreciate seeing the quadratic formula in the context of the graph of a parabola.
Good ol’ calculus will confirm that vertex (the lowest (or highest) point) of a parabola will lie on the line x = –b/(2a). From there, you just have to add or subtract some stuff to find where the parabola crosses the x-axis (of course, sometime you have to use your imagination to “see” the crossings). This is why we have the “plus or minus” in the quadratic formula. Parabolas are symmetrical.
Any calculus students out there, I invite you to tell us quickly how to confirm the business about the vertex.