已知x-2y=3,求x²-4xy+4y²-3x+6y的值.
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已知x-2y=3,求x²-4xy+4y²-3x+6y的值.
已知x-2y=3,求x²-4xy+4y²-3x+6y的值.
已知x-2y=3,求x²-4xy+4y²-3x+6y的值.
x^2-4xy+4y^2-3(x-2y)
=(x-2y)^2-3(x-2y)
=9-3*3
=0
0
x²-4xy+4y²-3x+6y=(x-2y)^2-3(x-2y)=9-9=0
x²-4xy+4y²-3x+6y
=(x-2y)²-(3x-6y)
=(x-2y)²-3(x-2y)
把x-2y=3代入代数式
(x-2y)²-3(x-2y)
=3²-3x3
=0
谢谢采纳啊
x²-4xy+4y²-3x+6y=(x-2y)(x-2y)-3(x-2y)=0