1. **Problem:** Given that $a = 4$, $b = -2$, and $c = -3$, evaluate $\frac{3ac}{b}$. 2. **Formula:** The expression is $\frac{3ac}{b}$. We substitute the values of $a$, $b$, and $c$ into the expression. 3. **Substitution:** $$\frac{3 \times 4 \times (-3)}{-2}$$ 4. **Multiplication in numerator:** $$3 \times 4 = 12$$ $$12 \times (-3) = -36$$ 5. **Expression becomes:** $$\frac{-36}{-2}$$ 6. **Simplify the fraction:** $$\frac{\cancel{-36}}{\cancel{-2}} = 18$$ 7. **Answer:** The value of $\frac{3ac}{b}$ is **18**.