Tangent to a circle where m=1

Hi,

I have the equation of a circle, and hence I also know the centre and the radius. I need to find the tangent/s of gradient 1.

I have tried it many times by letting y=x + g the equation of the line and substituting it into the equation of the circle. Then solving using the quadratic formula, then solving for g.

I'm pretty sureI'm doing this wrong, because I get g=some surd, but I know it's going to be a neat answer, i.e. probably a whole number!

I've tried loads of times but I my method is wrong. Can anyone help?

Thank