The line x−23=y+12=z−1−1intersects the curve xy=c2, z= 0 if c is equal to

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