those denominators are equal, trust me. Are you experiecned with completing the square; it's a good method to have down for calculus. Here's how I would have gone about it.
[itex]x^2-2x+5=x^2-2x+1+4=(x-1)^2+4[/itex]
Right? Because to copmplete the square you take half of -2 and square it, which is 1.