Dissociated mentioned using fabric glue, which I have yet to try it myself.
But if you're pressed with time, you can also use a double-sided tape. It costs $2-3 per 10 yrd ( I think)...enough to hem 2-3 pairs of jeans tmeporarily. The tape usually comes off when you wash your jeans.
OR.......hand hem your jeans, no sewing machine needed. Just a good iron to press them at the end.
I just did my DHV A last night.
Slipstich (hidden stitch) on the outer...
On the inside (wrongside)...just regular stitching.