化简求值①2(4m²n²-3n³)+5(-3m²n²+4n³),其中m=3,n-1②3x²y-[2xyz-(2xyz-x²yz)+3x²y],其中x=-4,y=2分之1,z=3
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![化简求值①2(4m²n²-3n³)+5(-3m²n²+4n³),其中m=3,n-1②3x²y-[2xyz-(2xyz-x²yz)+3x²y],其中x=-4,y=2分之1,z=3](/uploads/image/z/601800-24-0.jpg?t=%E5%8C%96%E7%AE%80%E6%B1%82%E5%80%BC%E2%91%A02%284m%26%23178%3Bn%26%23178%3B-3n%26%23179%3B%29%2B5%28-3m%26%23178%3Bn%26%23178%3B%2B4n%26%23179%3B%29%2C%E5%85%B6%E4%B8%ADm%3D3%2Cn-1%E2%91%A13x%26%23178%3By-%5B2xyz-%EF%BC%882xyz-x%26%23178%3Byz%EF%BC%89%2B3x%26%23178%3By%5D%EF%BC%8C%E5%85%B6%E4%B8%ADx%3D-4%EF%BC%8Cy%3D2%E5%88%86%E4%B9%8B1%EF%BC%8Cz%3D3)
化简求值①2(4m²n²-3n³)+5(-3m²n²+4n³),其中m=3,n-1②3x²y-[2xyz-(2xyz-x²yz)+3x²y],其中x=-4,y=2分之1,z=3
化简求值①2(4m²n²-3n³)+5(-3m²n²+4n³),其中m=3,n-1
②3x²y-[2xyz-(2xyz-x²yz)+3x²y],其中x=-4,y=2分之1,z=3
化简求值①2(4m²n²-3n³)+5(-3m²n²+4n³),其中m=3,n-1②3x²y-[2xyz-(2xyz-x²yz)+3x²y],其中x=-4,y=2分之1,z=3
2(4m²n²-3n³)+5(-3m²n²+4n³),其中m=3,n-1
=8m²n²-6n³-15m²n²+20n³
=14n³-7m²n²
然后代入计算:最后=49
我采用的是传统的方法,
3x²y-[2xyz-2xyz+x²yz+3x²y]
=3x²y-[x²yz+3x²y]
=3x²y-x²yz-3x²y
=-x²yz
当x=-4,y=2分之1,z=3时
原式=-24
5 5 5 5 5