Question

if a+b+c= 6,a square+b square+c spuare =14 then ,ab+bc+ca=​

Answer 1

given :-

(a+b+c) = 6

$a^2 + b^2 + c^2 = 14$

find :-

ab + bc + ca

formulae used :-

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

putting values :-

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

$6^2 = 14+ 2(ab + bc + ca)$

36 = 14 + 2(ab+bc+ca)

36-14 = 2(ab+bc+ca)

2(ab+bc+ca) = 22

ab + bc + ca = 22/2

ab + bc +ca = 11

answer:-

ab + bc + ca = 11