Shelly and terrence completed a different number of tasks in a game. shelly earned 90 points on each task. terrence's total points were 20 less than shelly's total. the expression below shows terrence's total points in the game: 90x − 20 what does the factor x of the first term of the expression represent?

The weight of a radioactive isotope was 96 grams at the start of an experiment. after one hour, the weight of the isotope was half of its initial weight. after two hours, the weight of the isotope was half of its weight the previous hour. if this pattern continues, which of the following graphs represents the weight of the radioactive isotope over time? a. graph w b. graph x c. graph y d. graph z