To divide fractions, you can multiply by the reciprocal of the divisor.
So, for the expression \(-\frac{3}{4} \div \left(-\frac{4}{5}\right)\), it can be rewritten as:
\[ -\frac{3}{4} \times -\frac{5}{4} \]
Now, multiply the numerators and the denominators:
\[ =\frac{(-3) \times (-5)}{4 \times 4} = \frac{15}{16} \]
So the answer is:
15/16