What is -66 2/3 - 24 1/8 + -78 3/4

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?

What expression is equivalent to 1/2(2+3x-6)

Solve: 3x+y=6 4x-2y=18 show all work !