From Förberedande kurs i matematik 2

Two cases:

• Choose \displaystyle \,a=8\, and \displaystyle \,b=-3\,. The solutions are \displaystyle \,z=1\, (triple root) and \displaystyle \,z=-3\,.
• Choose \displaystyle \,a=-8\, and \displaystyle \,b=-3\,. The solutions are \displaystyle \,z=-1\, (triple root) and \displaystyle \,z=3\,.