When you dispose of an asset with a section 179 expense deduction, the disposition isn't included on Form 4684, 4797, 6252, or 8824. Section 179 allows eligible businesses to deduct the full purchase price of qualifying equipment in the year it was put into service.Journal entry, debit depreciation expense, credit accumulated depreciation. Section 179 is an immediate expense deduction business owners take for purchases of depreciable business equipment instead of capitalizing an asset.