If a + b + c =0, then,   =

11

If 3x+ =7, then =

12

If a²+b² + c²-ab-bc-ca =0, then

14

If a^1/3+b^1/3 + c^1/3 =0, then

15

If a+b+ c =9 and ab + bc + ca = 23, then a²+b² + c²=