bk2 p41 q48

question : given the curve C: $\displaystyle y = x^3$ and P(h,k) is a point on C , where h and k are non-zero no.

(a)find the equation of the tangent to C at P

(b) if the tangent found in (a) intersects C again at Q , find the coordinates of Q.

my working:

$\displaystyle dy/dx = 3x^2$

equ. $\displaystyle : y= 3h^2 (x-h)+k $

sub to C

$\displaystyle x^3 - 3h ^2 x +3h^3 -k = 0$

don't know how to solve and find Q

thanks!