Question

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

Answer 1

Step-by-step explanation:

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

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

=> -2(ab+bc+ca)=20

=> ab+bc+ca = 20/-2= -10