1. **State the problem:** Solve for $w$ in the equation $$12 = - \frac{3}{5} w$$. 2. **Formula and rules:** To isolate $w$, we need to divide both sides of the equation by the coefficient of $w$, which is $-\frac{3}{5}$. Dividing by a fraction is the same as multiplying by its reciprocal. 3. **Isolate $w$:** $$w = \frac{12}{- \frac{3}{5}}$$ 4. **Multiply by the reciprocal:** $$w = 12 \times - \frac{5}{3}$$ 5. **Simplify multiplication:** $$w = - \frac{12 \times 5}{3}$$ 6. **Simplify the fraction:** $$w = - \frac{\cancel{12}^4 \times 5}{\cancel{3}^1} = - 4 \times 5$$ 7. **Final answer:** $$w = -20$$