Question

When isaac opens a book, the product of the page nuumbers on the open pages is 420?

Answer 1

x(x+1)=420

x²+x-420=0

(x+21)(x-20 )=420

x = -21 or +20. since we don't use negative page numbers discard -21 and let x be 20. the 2 pages are thus 20 and 21