The lengths of the axes of the hypberbola 9x2−16y2+72x−32y−16 = 0 are
16,9
8,6
4,3
18,8
9x2−16y2+72x−32y−16 = 0
⇒ 9 ( x2 + 8x) - 16(y2 + 2y) = 16
⇒ 9(x+4)2−16(y+1)2=144−16+16
⇒ (x+4)216−(y+1)29=1
a = 4 ⇒ 2a = 8
b = 3 ⇒ 2b = 6