$ Function
Source: AMC 12 2008B Problem 7
February 29, 2008
functionAMC
Problem Statement
For real numbers and , define a\$b\equal{}(a\minus{}b)^2. What is (x\minus{}y)^2\$(y\minus{}x)^2?
(A)\ 0 \qquad
(B)\ x^2\plus{}y^2 \qquad
(C)\ 2x^2 \qquad
(D)\ 2y^2 \qquad
(E)\ 4xy