Please help what's the answer

Use the elimination method to solve the system of equations -x+5y=-4 and 4x+3y=16

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?

If value of cos330° is √3/2 then find tan165°.