a³+8b³+27c³-18abc? please give answer
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Answered by
1
Hi ,
a + 2b + 3c = 0 ---( 1 )
a + 2b = - 3c ---( 2 )
( a + 2b )³ = ( - 3c )³
a³ + ( 2b )³ + 3 × a × 2b ( a + 2b ) = - 27c³
a³ + 8b³ + 27c³ + 6ab × ( - 3c ) = 0
[from ( 2 ) ]
a³ + 8b³ + 27c³ - 18abc = 0
a³ + 8b³ + 27c³ = 18abc
Hence proved ..
Answered by
1
Answer:
a + 2b +3c = 0
a + 2b = -3c
(a+2b)³= (+3c)³
a³ + (2b)³ + 3 ×a ×2b (a+2b) = -27c³
a³ + 8b³ + 27c³ +6ab × - (3c) = 0
a³+ 8b³+ 27c3 -18abc = 0
a³+8a³+27c³ = 18abc
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