1. **State the problem:** Find $x$ if $\log_3(2x + 5) = 5$. 2. **Recall the logarithm definition:** $\log_b(a) = c$ means $b^c = a$. 3. **Apply the definition:** From $\log_3(2x + 5) = 5$, we get $$3^5 = 2x + 5$$ 4. **Calculate $3^5$:** $$3^5 = 3 \times 3 \times 3 \times 3 \times 3 = 243$$ 5. **Set up the equation:** $$243 = 2x + 5$$ 6. **Solve for $x$:** $$2x = 243 - 5 = 238$$ $$x = \frac{238}{2} = 119$$ 7. **Answer:** $$\boxed{119}$$