The correct answers are The soup is too salty to eat. and The cake wasn't sweet enough for the guests.

Too comes before adjectives and adverbs to mean "more than necessary" (e.g., too salty, too spicy).

Enough comes after adjectives and adverbs to mean "sufficient" (e.g., sweet enough, long enough).

"The bread was baked enough long" is incorrect because enough should come after the adverb long (long enough). "The sauce was too much spicy" is incorrect because we just use too before adjectives, not too much.