The sum of 3 numbers is 131. the second of three numbers is seven more than twice the first. the third number is 12 less than the first

How to do this , and can some one explain

John read the first 114 pages of a novel, which was 3 pages less than 1/3 of the novel. write an equation to determine the total number of pages (p)(p) in the novel.

Varies inversely with x. if y=8.5 when x=-1 find x when y=-1