Element X decays radioactively with a half life of 9 minutes. If there are 170 grams of Element X, how long, to the nearest tenth of a minute, would it take the element to decay to 26 grams? y
=
a
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5
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t
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y=a(.5)
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Complete the square to determine the minimum or maximum value of the function defined by the expression. x2 − 12x − 2 a) maximum value at 38 b) minimum value at 38 c) maximum value at −38 d) minimum value at −38

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

Martha has a deck of cards. she has lost some of the cards, and now the deck only contains nine spades, eleven diamonds, eight clubs, and twelve hearts. martha predicts that whenever she draws a card from the deck without looking, she will draw a club one-fifth of the time. which activity would best allow martha to test her prediction? a. randomly draw a card from the box and see if it is a club. b. randomly draw a card. then, continue to draw another card until all eight clubs are drawn. c. randomly draw and replace a card 120 times. then, observe how close to 30 times a club is drawn. d. randomly draw and replace a card 100 times. then, observe how close to 20 times a club is drawn.