Solve for elimination x-4y= -9 and -x+3y=7

Describe how making an ‘and’ compound sentence effects your solution set

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

Need asap i will give brainliest and 98 points classify each pair of numbered angles corresponding, alternate interior, alternate exterior or none o these