Question

find the value of
ab+bc+ca
if a+b+c=9
and a^2+b^2+c^2=35

Answer 1

A+b+c =9

Squaring both sides
Asquare +Bsquare +Csquare +2 (ab+bc+ac) = 81

35 +2 (ab+bc+ac) = 81
Ab +bc +AC = 46/2
ab+bc+ac = 23

Hope you get your answer.

Answer 2

Heya,

(a+b+c)²= a²+b²+c²+2(ab+bc+ca)

=>9²=35 + 2(ab + bc + ca)
=>2(ab+ bc+ ca) = 81-35 = 46
=> ab + bc + ca = 23

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Regards
Supersonu
Brainly star