Answer :

The given expression is

[tex]100+(n-2)^2=149[/tex]

First, we have to subtract 100 on each side

[tex]\begin{gathered} 100-100+(n-2)^2=149-100 \\ (n-2)^2=49 \end{gathered}[/tex]

Hence, the answer is the first option, that's the first step.

The reason for this first step is because we can't take a square root without getting rid of the terms 100, otherwise, the process would be wrong.