1. **State the problem:** Simplify the expression $5x(x-1)-4(x+1)$. 2. **Apply the distributive property:** Multiply each term inside the parentheses by the factor outside. $$5x(x-1) = 5x^2 - 5x$$ $$-4(x+1) = -4x - 4$$ 3. **Rewrite the expression:** $$5x^2 - 5x - 4x - 4$$ 4. **Combine like terms:** $$5x^2 - (5x + 4x) - 4 = 5x^2 - 9x - 4$$ 5. **Final simplified expression:** $$5x^2 - 9x - 4$$