On December 28, 2021, Videotech Corporation (VTC) purchased 10 units of a new satellite uplink system from Tristar Communications for $21,000 each. The terms of each sale were 1/10, n/30. VTC uses the gross method to account for purchase discounts and a perpetual inventory system. VTC paid the net-of-discount amount on January 6, 2022. Prepare the journal entries on December 28 and January 6 to record the purchase and payment. (If no entry is required for a transaction/event, select "No journal entry required" in the first account field.)