Ettiene solved a quadratic equation. His work is shown below.
**In which step did Ettiene make an error?**
$\begin{align}
\dfrac{3}{4}(x-6)^2+1&=28
\\\\
\dfrac{3}{4}(x-6)^2&=27&\text{Step }1
\\\\
(x-6)^2&=20\dfrac14&\text{Step }2
\\\\
x-6&=\pm\sqrt{20\dfrac14}&\text{Step }3
\\\\
x&=\pm\sqrt{20\dfrac14}+6&\text{Step }4
\end{align}$
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