Is it permissible for a resident whose workplace is 170 km away from his city to shorten and combine prayers?

If the distance between the last building of your city and your workplace is 83 kilometers or more, you are permitted to combine and shorten the four-rak'ah prayers to two rak'ahs. However, if you pray Dhuhr behind an Imam who completes the prayer, you must complete your prayer, and this is better than missing the congregational prayer. If you delay the Dhuhr prayer until Asr and pray them combined and shortened, your prayer is valid.