1. **Problem:** Calculate the value of the expression $$5a + 3b - 4$$ for $$a = -3$$ and $$b = -2$$. 2. **Formula and rules:** To evaluate an algebraic expression, substitute the given values for the variables and perform arithmetic operations following the order of operations. 3. **Substitution:** $$5a + 3b - 4 = 5(-3) + 3(-2) - 4$$ 4. **Calculate each term:** $$5(-3) = -15$$ $$3(-2) = -6$$ 5. **Sum all terms:** $$-15 + (-6) - 4 = -15 - 6 - 4$$ 6. **Simplify step-by-step:** $$-15 - 6 = -21$$ $$-21 - 4 = -25$$ 7. **Final answer:** $$\boxed{-25}$$