3 SAT Math Questions

MITer94
Fri, 08 Nov 2013 20:25:42 +0000

Here’s one way to do #19:

xy - x - y = 0

Add 1 to both sides and factor the LHS:

(x-1)(y-1) = 1

Since y > 2, y-1 > 1. Therefore x-1 is strictly between 0 and 1, or 1 < x < 2, D.