Question

. f a+b+c=7 and ab+bc+ca=20, find the value of a the​

Answer 1

Answer: a^2+b^2+c^2=9

Step-by-step explanation: let a^2+b^2+c^2=x

if you know the identities you can find the answer easily

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

(7)^2=x+2(20)

49=x+40

9=x

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