Plz help not much Plz be correct I don’t wanna fail

Show me how you find y and z and determine what y and z are you i appreciate it : )

Select the correct answer. joshua likes to read. he read 6 books when he was 6 years old. every year he doubled the number of books he read the previous year. how many total books did he read between the ages of 6 and 10? a. 60 b. 90 c.186 d.187

Find the difference (8ab+a+2) - (3ab+6)