Complete the proof AB is a diameter of circle O.
Given: AC and BD are tangents
Prove: AC BD
A
0
B
D

 r = - 1      or   r = 1/2

Step-by-step explanation:

From the quadratic equation;

          + 6r - 3r - 3 = 0

           ( + 6r) - (3r + 3) = 0

         6r(r + 1)  - 3 (r + 1) = 0

         ⇒ (r + 1) or (6r - 3) = 0

         r + 1 = 0     or 6r - 3 = 0

         r = - 1      or      6r = 3

         r = - 1      or   r = 1/2

Thus, the solutions to the equation are; r = - 1 or r = 1/2 since erx is never 0.