Last year, the school library had a total of x books. Over the summer, the library acquired another 31 books and now has a total
of 1,867 books. Which equation could be used to find x, the number of books the library had last year? A. x + 31 = 1,867 B. x - 31 = 1,867 C. 1,867 + x = 31 D. 31x = 1,867
