Annie tried to subtract two polynomials. Her work is shown below:
$\begin{align}
&\phantom{=}(k^2+2k-13)-(-3k^2+9k+1)
\\\\
&=k^2+2k-13+3k^2+9k+1&\text{Step }1
\\\\
&=(1+3)k^2+(2+9)k+(-13+1)&\text{Step }2
\\\\
&=4k^2+11k-12&\text{Step }3
\end{align}$
**At which step did Annie make an error, if at all?**
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