Question

x^2-2x-y-8=0
I need to find the standard form of the equation of this parabola. it is one of these 4 answers, johny came up with y=(x-4)(x+2)=x2 -2x -8 but it is not one of the given answers I have listed here.
y=(x-1)^2-9

y=(x-1)^2+9

y=(x+1)^2-9

y=(x+1)^2+9