Radius of a Circle: Solving Negative Equations

[chemic_23]

Homework Statement

Homework Equations

Why is there negative on h-2k+2?and a denominator of negative square root of 5?
also in 2h-k-17, it has a negative sign but the denominator is not negative square root of 5? I really don't understand this part... please explain

The Attempt at a Solution

 

[rl.bhat]

In this problem center of the circle lies between the two tangents. In such cases, to find the perpendicular distances, you have to make the constant C in the tangent positive.