What is 3k(-5k+21)+2(2.5k+90) < -- confused

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?

Franco wants to double the volume of the cone. what should he do?

If f(x)= 3x+6 which of the following is the inverse of f(x)