on december 28, 2024, tristar communications sold 18 units of its new satellite uplink system to various customers for $25,000 each. the terms of each sale were 2/10, n/30. tristar uses the net method to account for sales discounts. in what year will income before tax be affected by discounts, assuming that all customers paid the net-of-discount amount on january 6, 2025? by how much