Problem:
Define a@b=ab−b2 and a#b=a+b−ab2. What is 6#26@2?
Answer Choices:
A. −21
B. −41
C. 81
D. 41
E. 21
Solution:
The value of 6@2 is 6⋅2−22=12−4=8, and the value of 6#2 is 6+2−6⋅22=8−24=−16. Thus
6#26@2=−168=(A)−21
The problems on this page are the property of the MAA's American Mathematics Competitions