Answer:
[tex]y=(x-1)^2-9[/tex]
Step-by-step explanation:
[tex]y=x^2-2x-8[/tex]
To complete the square:
[tex]\frac{b}{2}=(-1)^2=1[/tex]
[tex]y=x^2-2x-8[/tex]
[tex]+9[/tex] [tex]+9[/tex]
[tex]y+9=x^2-2x+1[/tex]
[tex](x-1)^2=y+9[/tex]
[tex]-9[/tex] [tex]-9[/tex]
[tex]y=(x-1)^2-9[/tex]