Ifa²+b²+c²=20,anda+b+c=0,findab+bc+ca.

2

Factorize: x²-1-2a–a².

3

If a + b + c = 0, then write the value of a³+b³+c³.

5

If a + b + c = 9 and ab + bc + ca = 40, find a² + b² + c².

6

If a² + b² + c² = 250 and ab + bc + ca = 3, find a + b + c.