How can you tell if an expression factors as (a + b)(a - b)?

Anna’s mother prepares sauerkraut, a fermented dish made from finely cut cabbage and salt. lactobacillus bacteria present on the surface of the cabbage combine with salt to turn the cabbage into a crunchy, sour dish. what chemical process occurs to create this dish? a. alcoholic fermentation b. cellular respiration c. conservation d. lactic acid fermentation e. photosynthesis