How do you solve using the completing the square method x^2 - 8x = 9?

x^2 - 8x = 9=>x^2-8x-9=0=> (x-4)^2-25=0=> (x-4)^2-5^2=0=> [x-4+5]*[x-4-5]=0=> (x+1)*(x-9)=0
Hence the solutions are $x = - 1$ and $x = 9$