Answer:
[tex]x^2-4x+4[/tex]
Step-by-step explanation:
In order to complete the square, we need to half b and then square it. This allows us to find c.
In this case, the coefficient of x is b and the unknown term is c
From this, we can see that b = -4
First, we need to half it
[tex]-\frac{4}{2} \\\\-2[/tex]
Next we need to square it
[tex](-2)^2\\\\4[/tex]
This gives us our answer of 4.