If the IRS had discovered the quadratic formula -- the algorithm for solving a quadratic equation, in the style of an IRS tax form. (This has been floating around for a while; I'm just reviving it.)
It seems silly here because everyone knows the quadratic formula. But the cubic formula is quite ugly, and takes up a couple lines; it's better expressed as an algorithm, which basically says to make a few changes of variables that give a quadratic and then solve the resulting quadratic. (Certainly if one were in the business of solving cubics, one would probably memorize the algorithm, not the formula.) And I don't even want to think about writing down an explicit formula for the general solution of the quartic in terms of radicals.
But tax forms are really just walking ordinary people through dealing with calculations involving certain equations. Sometimes I think taxation would make more sense to me if I actually saw the equations.