1. **State the problem:** Simplify the expression $-2x + 3(4x - 5)$. 2. **Use the distributive property:** Multiply $3$ by each term inside the parentheses: $$3(4x - 5) = 3 \times 4x - 3 \times 5 = 12x - 15$$ 3. **Rewrite the expression:** Substitute back into the original expression: $$-2x + 12x - 15$$ 4. **Combine like terms:** Add the $x$ terms: $$-2x + 12x = (\cancel{-2} + \cancel{12})x = 10x$$ 5. **Final simplified expression:** $$10x - 15$$ **Answer:** a. $10x - 15$