If a + b + c = 22 and ab + bc + ca = 91abc, then the value of a(b2+c2)+b(c2+a2)+c(a2+b2)abc
If a + b + c = 0, then prove the following
(a) (b + c) (b − c) + a(a + 2b) = 0
(b) a(a2 − bc) + b(b2 − ca) + c(c2 − ab) = 0
(c) a(b2 + c2) + b(c2 + a2) + c(a2 + b2) = −3abc
(d)