$1.$ Record the sale of the truck that has an accumulated depreciation balance of $$18,000$ at the time of disposal$\mathrm{.}2.$ Record the sale of the truck that has an accumulated depreciation balance of $$12,000$ at the time of disposal$\mathrm{.}3.$ Record the sale of the truck that has an accumulated depreciation balance of $$21,000$ at the time of disposal.