1. **State the problem:** Solve for $x$ in the equation $2x + 4x = 9$. 2. **Combine like terms:** Since both terms on the left side contain $x$, add their coefficients: $$2x + 4x = (2 + 4)x = 6x$$ 3. **Rewrite the equation:** $$6x = 9$$ 4. **Isolate $x$:** Divide both sides by 6 to solve for $x$: $$x = \frac{9}{6}$$ 5. **Simplify the fraction:** $$x = \frac{3}{2}$$ **Final answer:** $$x = \frac{3}{2}$$