1. **State the problem:** Simplify the expression $x^2 + 5x + 2x$. 2. **Identify like terms:** The terms $5x$ and $2x$ are like terms because they both contain $x$ to the first power. 3. **Add like terms:** Combine $5x$ and $2x$ by adding their coefficients: $5 + 2 = 7$. 4. **Write the simplified expression:** The expression becomes $x^2 + 7x$. 5. **Final answer:** The simplified form of $x^2 + 5x + 2x$ is $$x^2 + 7x$$.