Question

how do cartels, monopolies, and trust increase profit

Answer 1

exploiting more efficiently

Answer 2

people and resources (:

Answer 3

Competing firms cannot control the price, because they have to sell at similar price to other firms. This price tends to be to meet at the market equilibrium, where average revenue meets marginal cost.

Monopolies, cartels, and trusts are able to control the price because they need to to compete over prices. Thus they will tend to set prices to be at a producer surplus maximizing point where marginal revenue meets marginal cost.