Find the area of the shaded region - please just show your first step in this process.

Rachel reads 1/5 of the pages of a book plus 12 pages on the first day. on the second day, she reads 1/4 of the remaining pages plus 15 pages. on the third day, she reads 1/3 of the remaining pages plus 18 pages. on the fourth day, she reads the remaining 70 pages. how many total pages are in the book?

Astudent simplified a rational expression as shown.

The parabola opens: y=√x-4 (principal square root) up down right left