Difference between revisions of "2008 AMC 12B Problems/Problem 7"

Revision as of 10:34, 2 February 2015

For real numbers $a$ and $b$ , define $a\textdollar b = (a - b)^2$ . What is $(x - y)^2\textdollar(y - x)^2$ ?

$\textbf{(A)}\ 0 \qquad \textbf{(B)}\ x^2 + y^2 \qquad \textbf{(C)}\ 2x^2 \qquad \textbf{(D)}\ 2y^2 \qquad \textbf{(E)}\ 4xy$

$\left[ (x-y)^2 - (y-x)^2 \right]^2$

$\left[ (x-y)^2 - (x-y)^2 \right]^2$

$[0]^2$

$0 \Rightarrow \textbf{(A)}$

2008 AMC 12B (Problems • Answer Key • Resources)
Preceded by Problem 6	Followed by Problem 8
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
All AMC 12 Problems and Solutions

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 ==Problem 7==
-For real numbers <math>a</math> and <math>b</math>, define <math>a&#036;</math>b = (a - b)^2<math>. What is </math>(x - y)^2&#036;<math>(y - x)^2</math>?
+For real numbers <math>a</math> and <math>b</math>, define <math>a\textdollar b = (a - b)^2</math>. What is <math>(x - y)^2\textdollar(y - x)^2</math>?
 <math>\textbf{(A)}\ 0 \qquad \textbf{(B)}\ x^2 + y^2 \qquad \textbf{(C)}\ 2x^2 \qquad \textbf{(D)}\ 2y^2 \qquad \textbf{(E)}\ 4xy</math>