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将4(x-y)²-9(x-y)²+5(y-x)²-4(x-y)²按(x-y)²合并同类型得数学A.-4x平方+4y²B.-14x²+14y²C.-14(x-y)²D.-4(x-y)²

题目详情
将4(x-y)²-9(x-y)²+5(y-x)²-4(x-y)²按(x-y)²合并同类型得【数学
A.-4x平方+4y² B.-14x²+14y² C.-14(x-y)² D.-4(x-y)²
▼优质解答
答案和解析
4(x-y)²-9(x-y)²+5(y-x)²-4(x-y)²
=4(x-y)²-9(x-y)²+5(x-y)²-4(x-y)²
=(4-9+5-4)(x-y)²
=-4(x-y)²