Question

if a^2+b^2+c^2=20 and a+b+c =0 find ab+bc+ca​

Answer 1

Answer:

see the attachment......

Answer 2

Step-by-step explanation:

a^2 + b^2 + c^2 = 20

a+b+c = 0

Expression of (a+b+c)^2 = { a^2 + b^2 +c^2 + 2(ab+bc+ca) }

0^2 = 20 + 2(ab+bc+ca)

-20 = 2(ab+bc+ca)

ab+bc+ca = -10