if a + 2 b + c =0; then show that a^3 + 8b^3 + c^3=6abc
Please solve it guys fast
Answers
Answered by
131
Hey !!
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Here is your answer !!!
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since !!
a + 2b + c = 0 ( Given )
a + 2b = - c
on cubing both sides !!
( a + 2b )3 = ( - c )3
a3 + 8b3 + 3 a×2b (a +2b ) = - c3
a3 + 8b3 + 6ab (a + 2b ) = - c3
As we know a + 2b = - c
so
a3 + 8b3 + 6ab (- c) = - c3
a3 + 8b3 +c3 -6abc = 0
a3 + 8b3 + c3 = 6abc
Proved !!
Hope this helps you ^ _ ^ !!!
===========
Here is your answer !!!
============================
since !!
a + 2b + c = 0 ( Given )
a + 2b = - c
on cubing both sides !!
( a + 2b )3 = ( - c )3
a3 + 8b3 + 3 a×2b (a +2b ) = - c3
a3 + 8b3 + 6ab (a + 2b ) = - c3
As we know a + 2b = - c
so
a3 + 8b3 + 6ab (- c) = - c3
a3 + 8b3 +c3 -6abc = 0
a3 + 8b3 + c3 = 6abc
Proved !!
Hope this helps you ^ _ ^ !!!
Avni511:
where 8 gone in third last step
Answered by
22
hello friend,
a + 2b + c = 0 ( Given )a + 2b = - con cubing both sides !!( a + 2b )3 = ( - c )3a3 + 8b3 + 3 a×2b (a +2b ) = - c3a3 + 8b3 + 6ab (a + 2b ) = - c3As we know a + 2b = - c soa3 + b3 + 6ab (- c) = - c3a3 + b3 +c3 -6abc = 0a3 + b3 + c3 = 6abc
If you like mark as brilent
a + 2b + c = 0 ( Given )a + 2b = - con cubing both sides !!( a + 2b )3 = ( - c )3a3 + 8b3 + 3 a×2b (a +2b ) = - c3a3 + 8b3 + 6ab (a + 2b ) = - c3As we know a + 2b = - c soa3 + b3 + 6ab (- c) = - c3a3 + b3 +c3 -6abc = 0a3 + b3 + c3 = 6abc
If you like mark as brilent
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