$3\mathrm{.}18$ Exercise. Find all solutions in the appropriate canonical complete

residue system modulo n that satisfy the following linear congruences:

$1.26$x $14.$mod $3/.$

$2.2$x $3.$mod $5/.$

$3.4$x $7.$mod $8/.$

$4.24$x $123.$mod $213/.($This congruence is tedious to do by trial and

error, so perhaps we should defer work on it for now and instead try

to develop some techniques that might help.$)$