Math Help - Length of subtangent, subnormal, tangent, and normal

1. Length of subtangent, subnormal, tangent, and normal

Reviewing for my board exam ... Got no idea in solving this problem.

Find the length of subtangent, subnormal, tangent and normal of $xy + 2x - y = 5$ at point (2,1)

a. 1, 1 / 3, sqrt of 10 / 2, sqrt of 10
b. 1, 3, 5, 7
c. 1, 3, sqrt of 10 / 3, sqrt of 10
d. -1 / 3, -3, sqrt of 10 / 3, sqrt of 10

2. First step:

Find the tangent and normal lines to the curve at $(2,1)$. You should respectively obtain:

$x+y-3=0,\quad x-y-1=0$

Regards.

Fernando Revilla