The equation of the chord, having mid-point as (x1,y1), of the hyperbola a2x2−b2y2=1 is given by T=S1....(i) where, T=a2xx1−b2yy1−1 and S1=a2x12−b2y12−1 According to the question,(x1,y1)=(5,3) and a2=16,b2=25 as 25x2−16y2=400⇒16x2−25y2=1∴165x−253y=1625−259[Using (i)]⇒125x−48y=625−144⇒125x−48y=481