Element X decays radioactively with a half life of 13 minutes. If there are 830 grams of Element X, how long, to the nearest tenth of a minute, would it take the element to
decay to 20 grams?
y = a(.5)

Select the correct answer from each drop-down menu. a system of equations and its solution are given below. system a complete the sentences to explain what steps were followed to obtain the system of equations below. system b to get system b, the equation in system a was replaced by the sum of that equation and times the equation. the solution to system b the same as the solution to system a.]