2a) Maya did 288+90=-20d but it really should be 288=90+20d. This is because 288 is the total amount of pages in the book. If we were to go by Maya's original equation, it would mean she added 90 pages to the book. Also, another error is that if we solved for d, we would get a negative number, which would mean negative days.
2b)I have no clue what TTQA is but the equation should be:
288=90+20d
198=20d
d=198/20
d=9.9
Since part of a day counts as a whole day, Maya will spend 10 days finishing the book
2c)This question is either a personal question that I can't really help you with or an extension to a question not in the picture. Either way, I'm not sure if I can answer this one. If it's a personal question, you can use past experiences to help you estimate. If it's an extension, use linear equations to solve or this(how many pages you read a day as a slope)