Final answer:
The absolute superlative of 'fácil' is 'facílísimo', which follows the standard Spanish formation by adding '-ísimo' to the base adjective. No change occurs with the letter 'l' or 'll' in forming the superlative.
Step-by-step explanation:
The absolute superlative form of 'fácil' (which means 'easy' in Spanish), involves a spelling change. In Spanish, the absolute superlative is often formed by adding the suffix '-ísimo' to the adjective. Therefore, the absolute superlative of 'fácil' becomes 'facílísimo'. The spelling change is the accent mark (á) which is kept to maintain the correct stress of the word. Additionally, 'fácil' does not undergo a change with the double l ('ll') or the single l, as those spelling rules apply to the pronunciation of the letter 'l' in different contexts.