Answer
$-\dfrac{1}{67108.864}$
Work Step by Step
The general formula to find the nth term of a Geometric sequence is given as: $ a_{n}=a_1r^{n-1}$
We are given that $ a_1=8000, r=-\dfrac{1}{2}; n=30$
Now, $ a_{30}=8000 \times (-\dfrac{1}{2})^{30-1}=8000 (-\dfrac{1}{2})^{29}$
$\implies a_{30}=-\dfrac{1}{67108.864}$