这些初二计算题怎么写?步骤要出来,x²-(x-y)²(x+2y)²-(2x-y)²(x+y+z)²-(x-y-z)²(a-b) ^4-(b-a)²
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这些初二计算题怎么写?步骤要出来,x²-(x-y)²(x+2y)²-(2x-y)²(x+y+z)²-(x-y-z)²(a-b) ^4-(b-a)²
这些初二计算题怎么写?步骤要出来,
x²-(x-y)²
(x+2y)²-(2x-y)²
(x+y+z)²-(x-y-z)²
(a-b) ^4-(b-a)²
这些初二计算题怎么写?步骤要出来,x²-(x-y)²(x+2y)²-(2x-y)²(x+y+z)²-(x-y-z)²(a-b) ^4-(b-a)²
x²-(x-y)²
=x²-x²+2xy-y²
=2xy-y²
(x+2y)²-(2x-y)²
=x²+4xy+4y²-4x²+4xy-y²
=3y²+8xy-3x²
(x+y+z)²-(x-y-z)²
=(x+y+z-x+y+z)(x+y+z+x-y-z)
=(2y+2z)*2x
=4xy+4xz
(a-b) ^4-(b-a)²
=(a-b)²[(a-b)²-1)
=(a²-2ab+b²)(a²-2ab+b²-1)
=a^4-2a³b+a²b²-a²-2a³b+4a²b²-2ab³+2ab+a²b²-2ab³+b^4-b²
=a^4-4a³b+6a²b²-a²-4ab³-b²+^4
额
分解因式:a^2-b^2=(a+b)(a-b)
所以:X^2-(X-Y)^2=(X+X-Y)(X-X+Y)=(2X-Y)*Y=2XY-Y^2
以此类推就解出来了