Most independent works come in multiple variants (typically 1–4). Ensure you are looking at the correct variant number for the answers you need.
Finding a specific "Reshebnik" from 1994 can be tricky because these were often published as teacher's aids rather than student textbooks. However, you can find digital versions and community-solved problems on several platforms: a.p.shestakov 1994 reshebnik 8 klass
Solving complete and incomplete quadratic equations, using the discriminant, and Vieta's theorem. Most independent works come in multiple variants (typically
Properties of arithmetic square roots and transformations of expressions containing them. using the discriminant
If you are searching online, use the keywords "Шестаков 8 класс самостоятельные работы" as this is how the collection is most commonly titled in digital archives.