Given the common difference and the first term of an arithmetic sequence, which formula, the recursive or explicit formula, would be more useful to determine a500? Explain your answer change if you knew the value of a499? Explain

This is so harddd! solve. 1 + 1 = solve 4 + 4 = solve 3 x 3

Logan wants to know how many skateboards have defective parts. he inspects 20,000 skateboards and keeps track of the number of defects per board. use his probability distribution table to find the expected value for defects on a skateboard.

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.