Simplify: 15w6 + (-5w6)

plz help !!!

80 points suppose marcy made 45 posts online. if 23 of them contained an image, what percent of her posts had images? round your answer to the nearest whole percent. 54 percent 51 percent 49 percent 48 percent

Novak gives 9 packs of paper to a group of 5 students. if the group shares the paper equally how many packs of paper does each student get. write the a answer as a mixed number

Since we have computer algebra systems that can solve polynomial division problems for us, why is it necessary to learn how to do these things by hand?