Answer:
[tex]y = (x-2)^{2} -4[/tex]
Step-by-step explanation:
To complete the square: add 4 to both sides because the product of 4 as 2 as the factor which 2 * 2 so [tex]2^{2}[/tex]
[tex]y + ? = x^{2} - 4x + ?[/tex]
[tex]y + 2^{2} = x^{2} - 4x + 2^{2}[/tex]
[tex]y + 4 = x^{2} - 4x + 4[/tex]
Now we can factor the expression
[tex]y + 4 = (x-2)^{2}[/tex]
Move the 4 to the other side to isolate y which changes the sign
[tex]y = (x-2)^{2} - 4[/tex]
