if a+b+c=12 and a²+b²+c²=64, find the value of (ab+bc+ca).
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Answered by
4
Answer:(a+b+c)^2=(12)^2
a^2+b^2+c^2+2(ab+bc+ca)=144
64+2 (ab+bc+ca)=144
2(ab+bc+ca)=80
ab+bc+ca=40
Step-by-step explanation:
Answered by
5
Answer:
(a+b+c)² = (12)²
a²+b²+c²+2ab+2bc+2ca = 144
{a²+b²+c²}+2ab+2bc+2ca = 144
64 + 2(ab+bc+ca) = 144
2(ab+bc+ca) = 144 - 64
2(ab+bc+ca) = 80
ab+bc+ca = 80/2
ab+bc+ca = 40 ......Ans
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