1. **State the problem:** Solve the equation $$3x + 19 = 40$$ for $$x$$. 2. **Isolate the term with $$x$$:** Subtract 19 from both sides to get rid of the constant on the left. $$3x + 19 - 19 = 40 - 19$$ $$3x = 21$$ 3. **Solve for $$x$$:** Divide both sides by 3 to isolate $$x$$. $$\frac{\cancel{3}x}{\cancel{3}} = \frac{21}{3}$$ $$x = 7$$ 4. **Final answer:** $$x = 7$$