Allison is evaluating the expression Negative 5 minus (negative 2) using integer tiles. She begins with 5 negative tiles as shown. 5 negative tiles. What should Allison do next to find the value of the expression? remove 2 negative tiles remove 3 negative tiles add 2 negative tiles add 7 negative tiles

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