Explanation:
1. First divide by the leading term, making the polynomial monic.
2. Then, given x
2 + a1x + a0, substitute x = y − a1 to obtain an equation without the linear term.
(This is the “depressed” equation.)
3. Solve then for y as a square root. (Remember to use both signs of the square root.)
4. Once this is done, recover x using the fact that x = y − a1