Question 154840
x^2-(x-y)^2
X^2-(X^2-2XY+Y^2)
2XY-Y^2 ANSWER.
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(x+y)^2-(x-y)^2
X^2+2XY+Y^2-(X^2-2XY+Y^2)
X^2+2XY+Y^2-X^2+2XY-Y^2
4XY ANSWER.