We are asked to find the integral of \( 2x + 1 \). The general rule for integrating \( ax^n \) is \( \frac{a}{n+1} x^{n+1} \). For this question, the integral is as follows:
\[
\int (2x + 1) \, dx = x^2 + x + k.
\]
Thus, the final result is \( x^2 + x + k \).