Which polygon has 20 diagonals? Calculate the sum of the interior angles of that polygon. ITS TIMED PLS HELP​

What is the explicit rule for the sequence in simplified form? −1,−4,−7,−10,−13… an=4−5n an=−4−3n an=2−3n an=−6−5n

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The high temp today was 62°. when nighttime comes, the temp will drop 40°. by 4am the temp will drop an additional 40°. what is the temp at 4am?