If the line  x−23=y+12=z−1−1 and the curve xy=c2,z=0 intersect each other then the value of  c is

We have z = 0 for the point, where the line intersects the curve. Therefore,  x−23=y+12=0−1−1⇒ x−23=1 and y+12=1⇒ x=5 and y=1 Putting these values in xy=c2, we get 5=c2 or c=±5