If you were to solve the following system by substitution, what would be the best variable to solve for and from what equation? 2x+6y=9 3x-12y=15

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?

Two angles are complementary. the large angle is 36 more than the smaller angle. what is the measure of the large angle?

If you are trying to move an attached term across the equal sign (=), what operation would you use to move it?