2006 AMC 12B Problems/Problem 2

Problem

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

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

$4\spadesuit 5=-9$

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

2006 AMC 12B (Problems • Answer Key • Resources)
Preceded by Problem 1	Followed by Problem 3
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