Author: adamsmith2009 Posted: Tue Dec 08, 2009 5:41 pm (GMT -8) 1) x(x-1) = 20 2) 2^9 Explanation: 1. 3^X – 3^(X-1)= 162 then x(x-1) = Factor: 3^(x-1)*(3-1) = 162 3^(x-1)(2) = 162 Divid 2 by both sides: 3^(x-1) = 81 Solve for x – 3^4 = 81. So x would be 5 and 5*4=20 2

Read the original: 
Problem Solving :: RE: GMAT Prep Que