The Galaxy will make their second MLS Cup appearance in three years after downing RSL to win the MLS Western Conference final.
Robbie Keane added an insurance goal 10 minutes later and Landon Donovan scored on a first-half penalty kick for the Galaxy, who will be making a league-record seventh overall appearance in the final.
They will take on the Houston Dyanmo Nov. 20 at Home Depot Center in Carson, Calif.
Houston defeated Sporting Kansas City in Sunday's Eastern Conference final.
Alvaro Saborio scored in 26th minute for Salt Lake.
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