Answer :

Certainly! Let's simplify each of the given mathematical expressions step by step.

### Expression 1:
[tex]\[ \frac{1}{z^{-3}} \][/tex]

To simplify this, recall that [tex]\(z^{-3}\)[/tex] can be rewritten as [tex]\(\frac{1}{z^3}\)[/tex]. Applying this, we get:
[tex]\[ \frac{1}{z^{-3}} = z^3 \][/tex]
So, the simplified form of [tex]\(\frac{1}{z^{-3}}\)[/tex] is [tex]\(z^3\)[/tex].

### Expression 2:
[tex]\[ -3z \][/tex]

This expression is already in its simplest form. There are no further simplifications needed. Hence, the simplified form is:
[tex]\[ -3z \][/tex]

### Expression 3:
[tex]\[ \frac{1}{-z^3} \][/tex]

To simplify this, recognize that a negative exponent retains its effect:

Since [tex]\(-z^3\)[/tex] remains in the denominator, the negative sign can be factored out as follows,
[tex]\[ \frac{1}{-z^3} = -\frac{1}{z^3} \][/tex]
This is the simplified form of the expression.

### Expression 4:
[tex]\[ z^3 \][/tex]

This expression is already in its simplest form. Therefore, the simplified form is:
[tex]\[ z^3 \][/tex]

Putting it all together, the simplified forms of the given expressions are:
1. [tex]\(\frac{1}{z^{-3}}\)[/tex] simplifies to [tex]\(z^3\)[/tex].
2. [tex]\(-3z\)[/tex] stays [tex]\(-3z\)[/tex].
3. [tex]\(\frac{1}{-z^3}\)[/tex] simplifies to [tex]\(-\frac{1}{z^3}\)[/tex].
4. [tex]\(z^3\)[/tex] stays [tex]\(z^3\)[/tex].

Thus, the final results are:
[tex]\[ (z^3, -3z, -1/z^3, z^3) \][/tex]