Question

If a square + b square + c square= 29 and a+b+c=9,find ab +bc+ca

Answer 1

Answer:

26

Step-by-step explanation:

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

9^2 =29+2(ab+bc+ca)

81-29=2(ab+bc+ca)

26=ab+bc+ca