2m³-11
Explain this expression

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?

How many ordered pairs of positive integers satisfy xy=32?

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle