Question
If $a - 2b + 3c = 0;$ state the value of $a^3- 8b^3+ 27c^3.$
✓
Answer
$a^3- 8b^3+ 27c^3= a^3+ (-2b)^3+ (3c)^3$ Since $a - 2b + 3c = 0,$
we have
$a^3- 8b^3+ 27c^3= a^3+ (-2b)^3+ (3c)^3$
$= 3(a)( -2b)(3c)$
$= -18abc$
we have
$a^3- 8b^3+ 27c^3= a^3+ (-2b)^3+ (3c)^3$
$= 3(a)( -2b)(3c)$
$= -18abc$
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