Drag and drop the expressions into the boxes to correctly complete the proof of the polynomial identity.
Are you using Khan Academy? You know if you got the question wrong they would give you an answer and explanation.
First box: x4 - 2x2y2 + y4
Second box: 2x4 - 2x2y2 + 2y4
Third box: 2(x4 - x2y2 + y4)