simplify 12r+5s-7t+11r+9s-4r
20r+14s-7tAdd 12r + 11r than subtract 4R Add 5s and 9s -7t stays the sameBASICALLY COMBINE LIKE TERMS TO GET THE ANSWER
12r+5s-7t+11r+9s-4rTo simplify, all you must do is combine like terms.Final Answer: 19r+14s-7t