作业帮已知（a＋2）²+丨3b-1丨=0,求3a²b-[3ab²-6（ab-½a²b）+4ab]-2ab的值
来源：学生作业帮助网 编辑：作业帮 时间：2024/07/10 14:47:52
![已知（a＋2）²+丨3b-1丨=0,求3a²b-[3ab²-6（ab-½a²b）+4ab]-2ab的值](/uploads/image/z/5295664-64-4.jpg?t=%E5%B7%B2%E7%9F%A5%EF%BC%88a%EF%BC%8B2%EF%BC%89%26%23178%3B%2B%E4%B8%A83b-1%E4%B8%A8%3D0%2C%E6%B1%823a%26%23178%3Bb-%5B3ab%26%23178%3B-6%EF%BC%88ab-%26%23189%3Ba%26%23178%3Bb%EF%BC%89%2B4ab%5D-2ab%E7%9A%84%E5%80%BC)
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已知（a＋2）²+丨3b-1丨=0,求3a²b-[3ab²-6（ab-½a²b）+4ab]-2ab的值
已知（a＋2）²+丨3b-1丨=0,求3a²b-[3ab²-6（ab-½a²b）+4ab]-2ab的值
已知（a＋2）²+丨3b-1丨=0,求3a²b-[3ab²-6（ab-½a²b）+4ab]-2ab的值
（a＋2）²+丨3b-1丨=0
所以a+2=0,3b-1=0
a=-2,b=1/3
所以原式=3a²b-(3ab²-6ab+3a²b+4ab)-2ab
=3a²b-(3ab²-6ab+3a²b+4ab)-2ab
=3a²b-(6ab²-2ab)-2ab
=3a²b-6ab²+2ab-2ab
=-3a²b
=-3×4×1/3
=-4
因为﹙a＋2﹚²≥0，|3b－1|≥0，所以a=﹣2，b=1/3。再代进去算就可以得到答案了