Final answer:
Cost-plus regulation refers to government setting the price a firm can charge based on accounting costs and adding a normal profit rate, while price cap regulation allows the government to set price levels in advance.
Step-by-step explanation:
Cost-plus regulation refers to government regulating a firm by setting the price that the firm can charge over a period of time, based on the firm's accounting costs and adding a normal rate of profit. On the other hand, price cap regulation is when the government sets a price level several years in advance, and the firm's profitability depends on its ability to produce at lower costs or sell a higher quantity than expected.