Hello! To solve completing by the square, we have to follow some steps:
[tex]\begin{gathered} x^2-4x=1 \\ \end{gathered}[/tex]
Now, we have to add the same value in both sides (square):
If we factorize the first part of this expression, we can obtain:
Notice that we obtained the same expression, and now we know the value of the square. So, let's rewrite the first expression and replace the squares by 4:
