3. For the accompanying graphs (a) through (c), write down, if possible, a Hamiltonian circuit starting at X3.
3.
(a) Not possible
(b) A possible answer is X3X2X11X12X6X13X20X16X17X14X10X1X4X9X15X18X19X8X7X5X3
(c) X3X4X2X5X6X1X3