Question

If a + b + c = 11 and ab + bc + ca = 27, then find a² + b² + c²

Answer 1

a²+b²c²= a+b+c+2ab 2bc+2ca
= 11+2(ab+BC+ca)
= 11+2×27
=65

Answer 2

Step-by-step explanation:

a + b + c = 11

ab + bc +ca =27

find,

a ^2 +b^2 +c^2 =?

( a + b + c )^2 = a^2 + b^2 + c^2 + 2ab + 2bc +2ca

(11)^2 = a^2 + b^2 + c^2 + 2(ab + bc + ca)

121 = a^2 + b^2 + c^2 + 2(27)

121 = a^2 + b^2 + c^2 + 54

121 - 54 = a^2 + b^2 + c^2

67 = a^2 + b^2 + c^2

a^2 + b^2 + c^2 = 67