Question

Q5. If 3a +2b +C =0; then 27a3 + 8b3 +c3 =
(a)-8b3 (b) 18 (c) O (d) 18abc​

Answer 1

Answer:

3a+2b+c=0

➡3a+2b=-c

now,

27a^3+8b^3+c^3

$= {(3a)}^{3} + {(2b)}^{3} + {(c)}^{3}$

$= {(3a + 2b)}^{3} - 3.3a.2b(3a + 2b) + {c}^{3}$

$= {( - c)}^{3} - 18ab.( - c) + {c}^{3}$

=-c^3+18abc+c^3

=18abc

so,answer is option (d)➡18abc