Hi David. You are looking for help in Algebra, not Number Theory, right?

Here are some hints:

- 2.21: Expand the polynomial and compare with $ax^2 + bx + c = 0$, this should help getting rid of some terms. When looking at the solutions, you might want to use Vieta's formulas to rewrite them in terms of $x_1$ and $x_2$.

- 2.26: Try squaring $q$ and using Vieta's formulas.

- 2.27: Note Vieta's formulas tell you $-m = x_1 + x_2$, what is then $m^2$?