当a=2b=-2时求代数式3a3.b3-2⼀1a2b十b-(4a3b3-4⼀1a2b-b2)十(a

当a=2b=-2时求代数式3a3.b3-2/1a2b十b-(4a3b3-4/1a2b-b2)十(a3b3十4/1a2b-2b2
2025-06-21 18:42:09
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回答1:

3a³b³-1/2a²b十b-(4a³b³-1/4a²b-b²)十(a³b³十1/4a²b-2b²)
=3a³b³-1/2a²b+b-4a³b³+1/4a²b+b²+a³b³+1/4a²b-2b²
=b-b²
=2-(-2)²
=-2
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3a³b³-1/2a²b十b²-(4a³b³-1/4a²b-b²)十(a³b³十1/4a²b-2b²)
=3a³b³-1/2a²b+b²-4a³b³+1/4a²b+b²+a³b³+1/4a²b-2b²
=0
=2-(-2)²
=-2