a2+b2+c2=90 and a+b+c=20 find the value of ab+bc+ca
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3
your ans
given:-
a2+b2+c2=90
a+b+c=20
use formula
(a+b+c)2=a2+b2+c2+2(Ab+BC+ca)
(20)2=90+2(Ab+BC+ca)
400-90=2(Ab+BC+ca)
310÷2=155=Ab+BC+ca
given:-
a2+b2+c2=90
a+b+c=20
use formula
(a+b+c)2=a2+b2+c2+2(Ab+BC+ca)
(20)2=90+2(Ab+BC+ca)
400-90=2(Ab+BC+ca)
310÷2=155=Ab+BC+ca
mohiu:
its answer is 155
I did not know the method but i knw ans.
your divide is wrong
Answered by
2
(a+b+c)²=a²+b²+c²+2ab+2bc+2ac
(20)²=90+2(ab+BC+AC)
400-90=2(ab+BC+AC)
310/2=ab+BC+AC
155=ab+BC+AC
That's your answer
Hope it helps you!!!!!!!
please give 2nd answer
What do you mean by 2nd answer???
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