Question

(ii) a+b+c= 6, a2 +b2+c2 =14 then ab+bc+ca​

Answer 1

Since (a+b+c)²=a²+b²+c²+2(ab+bc+ca)

=> (6)²=14+2(ab+bc+ca)

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

=>22=2(ab+bc+ca)

=>ab+bc+ca=11

Hope it is helpful.