1. **State the problem:** Find the 10th term of a geometric sequence where the 1st term $a_1 = -3$ and the 4th term $a_4 = 81$.
2. **Recall the formula for the $n$th term of a geometric sequence:**
$$a_n = a_1 \cdot r^{n-1}$$
where $r$ is the common ratio.
3. **Use the given information to find $r$:**
$$a_4 = a_1 \cdot r^{3}$$
Substitute $a_4 = 81$ and $a_1 = -3$:
$$81 = -3 \cdot r^{3}$$
4. **Solve for $r^{3}$:**
$$r^{3} = \frac{81}{-3} = -27$$
5. **Find $r$ by taking the cube root:**
$$r = \sqrt[3]{-27} = -3$$
6. **Find the 10th term $a_{10}$:**
$$a_{10} = a_1 \cdot r^{9} = -3 \cdot (-3)^{9}$$
7. **Calculate $(-3)^9$:**
$$(-3)^9 = (-3)^{8} \cdot (-3) = (3^8) \cdot (-3) = 6561 \cdot (-3) = -19683$$
8. **Calculate $a_{10}$:**
$$a_{10} = -3 \cdot (-19683) = 59049$$
**Final answer:** The 10th term is $59049$, which corresponds to option d.
Geometric Sequence D28Fc0
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