Question

if a + b + c =9 and AB + BC + CA = 26 so find a square + b square + c square

Answer 1

Given that


(a + b + c) = 9

Let's sqaure both the sides :)

=> (a + b + c)² = (9)²

=> a² + b² + c² + 2ab + 2bc + 2ca = 81

[Using the identity]

=> a² + b² + c² + 2(ab + bc + ca) = 81

[By taking 2 as common]

But it's given that ab + bc + ca = 26

=> a² + b² + c² + 2(26) = 81

=> a² + b² + c² + 52 = 81

=> a² + b² + c² = 81 - 52

=> a² + b² + c² = 29.


Hope it helps dear friend ☺️✌️