Question

How do you do this. Please give a full answer and explain why.

Answer 1

Law of Exponent

$\displaystyle \large{ {a}^{ - n} = \frac{1}{ {a}^{n} } }$

Compare the terms.

$\displaystyle \large{ {a}^{ - n} = {( - 2)}^{ - 3} }$

Therefore, a = -2 and n = 3. From the law of exponent above, we receive:

$\displaystyle \large{ {( - 2)}^{ - 3} = \frac{1}{ {( - 2)}^{ 3} } }$

Exponent Def. (For cubic)

$\displaystyle \large{ {a}^{3} = a \times a \times a }$

Factor (-2)^3 out.

$\displaystyle \large{ {( - 2)}^{ - 3} = \frac{1}{( - 2) \times ( - 2) \times ( - 2)}}$

(-2) • (-2) = 4 | Negative × Negative = Positive.

$\displaystyle \large{ {( - 2)}^{ - 3} = \frac{1}{4 \times ( - 2)}}$

4 • (-2) = -8 | Negative Multiply Positive = Negative.

$\displaystyle \large{ {( - 2)}^{ - 3} = \frac{1}{ - 8}}$

If either denominator or numerator is in negative, it is the best to write in the middle or between numerator and denominators.

Hence,

$\displaystyle \large \boxed{ {( - 2)}^{ - 3} = - \frac{1}{ 8}}$

The answer is - 1 / 8