Question

If a^2+b^2+c^2=20 and and ab+bc+ca =8 find the value of a+b+c​

Answer 1

Answer:

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

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

20=(a+b+c)^2+2x8

20=(a+b+c)^2+16

20-16=(a+b+c)^2

4=(a+b+c)^2

2=a+b+c  (by taking square root)

Step-by-step explanation: