If x = 9 is the chord of contact of the hyperbola x²-y² = 9, then the equation of the corresponding pair of tangents is
a. 9x²-8y²+18x-9 = 0
b.9x²-8y²-18x+9 = 0
c. 9x²-8y²-18x-9 = 0
d. 9x²-8y²+18x=9 = 0
Comparing chord of contact of point (h,k) i.e.. hx-ky = 9 with x = 9, we get h =1, and k = 0.
Therefore pair of tangents is SS1 = T²