Explain the algebra 5a - 9a - (-2a) =

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Evan went to the park and saw for animals each animal was either a duck or dog if he saw a total of 14 legs how many of each animal did he see

Anew movie is released each year for 14 years to go along with a popular book series. each movie is 2 minutes longer than the last to go along with a plot twist. the first movie is 70 minutes long. use an arithmetic series formula to determine the total length of all 14 movies