Correct Answer - Option 3 : -343/729
Concept:
When deriving power of any negative number keep the following points in mind:
If the power is even natural number then the number given in the base will be positive.
If the power is odd natural number then the number given in the base will be negative.
Calculation:
Let the value of (-7/9)3 be x.
x = (-7/9)3
⇒ x = (-7/9) × (-7/9) × (-7/9)
⇒ x = -(7/9 × 7/9 × 7/9)
⇒ x = -343/729
∴ The value of (-7/9)3 is -343/729.