Bookmaking, like dutching, uses bets placed simultaneously on multiple selections to eliminate the unlikely outcomes and divide the locked in profit between the remaining selections. Unlike dutching, however where you are backing your selections, with bookmaking you lay the selections.
Dutching is a strategy that consists in placing back bets simultaneously in several selections. The goal is to cover as many probable outcomes as possible, while leaving out the least likely, splitting the profit equally among all the favourite selections. This strategy greatly minimises the risk associated with each bet.
Arbing or arbitrage betting is a trading technique where you bet on all the outcomes an event, exploiting the different prices provided by bookmakers and betting exchanges. The result is a risk free bet.
A scalper is someone who profits from short term movements in the underlying price of a market. They are an extremely short term trader. The aim is to make money on the spread between between the back and lay price.