当X-Y=1时 X4-XY3-X3Y-3X2Y+3XY2+Y4的值为详细过程

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当X-Y=1时 X4-XY3-X3Y-3X2Y+3XY2+Y4的值为详细过程

当X-Y=1时 X4-XY3-X3Y-3X2Y+3XY2+Y4的值为详细过程
当X-Y=1时 X4-XY3-X3Y-3X2Y+3XY2+Y4的值为
详细过程

当X-Y=1时 X4-XY3-X3Y-3X2Y+3XY2+Y4的值为详细过程
原式=(X^4-X^3Y)-(XY^3-Y^4)-(3X^2Y-3XY^2)
=X^3(X-Y)-(X-Y)Y^3-3XY(X-Y)
=X^3-Y^3-3XY
=(X-Y)(X^2+XY+Y^2)-3XY
=X^2-2XY+Y^2
=(X-Y)^2
=1

X4-XY3-X3Y-3X2Y+3XY2+Y4
=(X4-X3Y)-(XY3-Y4)-(3X2Y-3XY2)
=X3(X-Y)-Y3(X-Y)-3XY(X-Y)
=X3-Y3-3XY
=(X-Y)(X2+XY+Y2)-3XY
=X2+XY+Y2-3XY
=X2-2XY+Y2
=(X-Y)2
=1