143k views
4 votes
Determine the value of a^2 +b^2+c^2, if a+b+c=7 and ab+bc+ca=15​

User Shizik
by
8.6k points

1 Answer

7 votes

Answer:


\huge\boxed{\sf a^2+b^2+c^2 = 19}

Explanation:


\sf (a+b+c)^2 = a^2+b^2+c^2 +2(ab+bc+ca)\\\\Put \ a+b+c = 7 \ and \ ab+bc+ca = 15\\\\7^2 = a^2+b^2+c^2 + 2(15)\\\\ 49 = a^2+b^2+c^2 + 30\\\\49 - 30 = a^2+b^2 +c^2\\\\a^2+b^2+c^2 = 19\\\\\rule[225]{225}{2}

Hope this helped!

~AH1807

User Yo Ludke
by
8.6k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories