先化简在求值,2a的平方+3ab+b的平方-a的平方-ab-2b的平方,其中a的平方-b的平方=2，ab=-3

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解
2a²+3ab+b²-a²数首-ab-2b²薯余数
=(2a²-a²)+(3ab-ab)+(b²-2b²)
=a²+2ab-b²毁蠢
=(a²-b²)+2ab
=2+2×(-3)
=2-6
=-4

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