Using the parametric equations x=6*4^t-2 and y=3*(4^(-t))-2, Find the Cartesian equation of the curve in the form xy+ax+by=c

Firstly make t the subject for both equations
(x-7)/6=4^t
(y+2)/3=4^(-t)
Times them together to eliminate t
((x-7)/6)((y+2)/3) = (4^t)*(4^-t)=4^0=1
Rearrange to the form required
(x-7)(x+2)=18
xy-7y+2x-14=18
xy+2x-7y=32