Question

Find the value of ab+bc+ca if a+b+c =27 and a² +b²+c²=105​

Answer 1

I hope It will help you

Answer 2

Answer:

Use the identity,

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

As:

2*(ab+bc+ca)=2×92=184

And,

a^2+b^2+c^2=105

Therefore,

(a+b+c)^2=105+184=289

Now taking square root of both sides,

a+b+c=17

Hence,17 is the answer.