It's common not to explain where the quadratic formula comes from (which is silly, it's straightforward enough to show, but standard math education curricula ar

It's common not to explain where the quadratic formula comes from (which is silly, it's straightforward enough to show, but standard math education curricula are shot through with this blind formula memorization nonsense), but… do they really tell you you'll learn it in calculus? It's got nothing to do with calculus.