rectangular hyperbola

also last minute i cant figure out what to do
ok for part a) they said to prove that the tangent to the rectangular hyperbola with equation xy=c^2 (c>0) at the point (ct, c/t)
is this : t^2(y) + x = 2ct

i done that part
b)then the y say tangents are drawn from the point (-3,3) to the rectangular hyperbola with equation xy=16.
find the coordinates of the points of contact of these tangents with the hyperbola.

any help with b? please exam in an hr and a half!

xy = 16
c = ±4

substitute into t^2(y) + x = 2ct

for your eqns of tangents

t²y + x = ±8t

the point (-3,3) satisfies this eqn - so substitute x=-3, y=3 and solve for t.
Hence the tangent pts (ct, c/t)