If $2 a - 3 b = - 1$ and $a b = 12$

then

$8 a^{3} - 27 b^{3} =$

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Solution

$\Rightarrow (2 a - 3 b)^{3} = (8 a^{3} - 27 b^{3}) - 18 a b (2 a - 3 b)$

$\Rightarrow (- 1)^{3} = (8 a^{3} - 27 b^{3}) - (18) (12) (- 1)$

$\Rightarrow - 1 = (8 a^{3} - 27 b^{3}) + 216$

$\Rightarrow (8 a^{3} - 27 b^{3}) = - 216 - 1 = - 217$

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Similar questions

If $2 a - 3 b = - 1$ and $a b = 12$

then

$8 a^{3} - 27 b^{3} =$

2 a + 3 b + c = 0

8 a^{3} + 27 b^{3} + c^{3} = 18 a b c

a^{3} - 27 b^{3}

a - 3 b = - 6

a b = - 10

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

2 a + 3 b + c = 0

(2 a + 3 b)

8 a^{3} + 36 a^{2} b + 54 a b^{2} + 27 b^{3}

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