AoPSWiki
Want to learn how to tackle those tough MATHCOUNTS and AMC counting and probability problems? Check out Art of Problem Solving's Introduction to Counting & Probability by David Patrick.

2006 AMC 12B Problems/Problem 2

From AoPSWiki

Revision as of 03:12, 10 February 2008 by NuclearWaffle (Talk | contribs)
(diff) ← Older revision | Current revision (diff) | Newer revision → (diff)

Problem

For real numbers x and y, define x\spadesuit y = (x + y)(x - y). What is 3\spadesuit(4\spadesuit 5)?

\text {(A) } - 72 \qquad \text {(B) } - 27 \qquad \text {(C) } - 24 \qquad \text {(D) } 24 \qquad \text {(E) } 72

Solution

4\spadesuit 5=-9

3\spadesuit -9=-72 \Rightarrow \text{(A)}

See also

2006 AMC 12B (Problems • Resources)
Preceded by
Problem 1 		Followed by
Problem 3
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25
Retrieved from "http://www.artofproblemsolving.com/Wiki/index.php/2006_AMC_12B_Problems/Problem_2"
Looking for a challenging algebra text? Preparing for MATHCOUNTS or the AMC exams?
Check out Art of Problem Solving's Introduction to Algebra by Richard Rusczyk.
© Copyright 2008 AoPS Incorporated. All Rights Reserved. • Foundation • Privacy • Contact Us