1. **State the problem:** Simplify the expression $$-7(0.4t + 9t + 0.3) - 0.8t$$. 2. **Use the distributive property:** Multiply $$-7$$ by each term inside the parentheses. 3. **Calculate each multiplication:** $$-7 \times 0.4t = -2.8t$$ $$-7 \times 9t = -63t$$ $$-7 \times 0.3 = -2.1$$ 4. **Rewrite the expression:** $$-2.8t - 63t - 2.1 - 0.8t$$ 5. **Combine like terms (terms with $$t$$):** $$-2.8t - 63t - 0.8t = -(2.8 + 63 + 0.8)t = -66.6t$$ 6. **Final simplified expression:** $$-66.6t - 2.1$$ This is the simplest form of the given expression.