if a+b+c=6 and a^2+b^2+c^2 = 30 find ab+bc+ca
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2
Answer:
3
Step-by-step explanation:
a²+b²+c²=30
a+b+c=6
find ab+bc+ca
(a+b+c)²=a²+b²+c²+2ab+2bc+2ca
6²= 30 + 2ab+ 2bc+2ca
36= 30 + 2[ab+bc+ca]
36-30= 2[ab+bc+ca]
6= 2[ab+bc+ca]
6/2=[ab+bc+ca]
3=[ab+bc+ca]
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Answered by
1
Answer:
ab + bc + ca = 3
Step-by-step explanation:
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