Question
If $a - b = -8$ and $ab = -12,$ then $a^3 - b^3 =$
✓
Answer
Using,$ (a - b)^3 = a^3 - b^3 - 3ab(a - b)$
$\Rightarrow a^3 - b^3 = (a - b)^3 + 3ab(a - b)$
$\Rightarrow a^3 - b^3 = (-8)^3 + 3(-12) (-8)$
$\Rightarrow a^3 - b^3 = -512 + 288 = -224$
$\Rightarrow a^3 - b^3 = (a - b)^3 + 3ab(a - b)$
$\Rightarrow a^3 - b^3 = (-8)^3 + 3(-12) (-8)$
$\Rightarrow a^3 - b^3 = -512 + 288 = -224$
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