4x²-[2x-(x²-2x+3)-2(x²-3x)]
=4x²-2x+(x²-2x+3)+2(x²-3x)
=4x²-2x+x²-2x+3+2x²-6x
=7x²-10x+3
(x²-2xy+y²)-2(x²+2xy+y²)
=x²-2xy+y²-2x²-4xy-2y²
=-x²-6xy-y²
计算 4x²-[2x-(x²-2x+3)-2(x²-3x)] (x²-2xy+y²)-2(x²+2xy+y²)
计算 4x²-[2x-(x²-2x+3)-2(x²-3x)] (x²-2xy+y²)-2(x²+2xy+y²)
数学人气：348 ℃时间：2019-08-16 21:55:55
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