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导读 x+y=12(x+y)^2=12^2x^2+2xy+y^2=144x^2-2xy+y^2=144-4xy(x-y)^2=108因为x。
x+y=12(x+y)^2=12^2x^2+2xy+y^2=144x^2-2xy+y^2=144-4xy(x-y)^2=108因为x。
x+y=12(x+y)^2=12^2x^2+2xy+y^2=144x^2-2xy+y^2=144-4xy(x-y)^2=108因为x。