先化简再求值先化简再求值:4分之1x²y+3分之1x²y+3[-(9分之1x²y+xy)]+4分之3x²y,其中x=-1,Y=1.求解……很着急!
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![先化简再求值先化简再求值:4分之1x²y+3分之1x²y+3[-(9分之1x²y+xy)]+4分之3x²y,其中x=-1,Y=1.求解……很着急!](/uploads/image/z/1072859-59-9.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%E5%86%8D%E6%B1%82%E5%80%BC%E5%85%88%E5%8C%96%E7%AE%80%E5%86%8D%E6%B1%82%E5%80%BC%3A4%E5%88%86%E4%B9%8B1x%26%23178%3By%2B3%E5%88%86%E4%B9%8B1x%26%23178%3By%2B3%5B-%289%E5%88%86%E4%B9%8B1x%26%23178%3By%2Bxy%29%5D%2B4%E5%88%86%E4%B9%8B3x%26%23178%3By%2C%E5%85%B6%E4%B8%ADx%3D-1%2CY%3D1.%E6%B1%82%E8%A7%A3%E2%80%A6%E2%80%A6%E5%BE%88%E7%9D%80%E6%80%A5%21)
先化简再求值先化简再求值:4分之1x²y+3分之1x²y+3[-(9分之1x²y+xy)]+4分之3x²y,其中x=-1,Y=1.求解……很着急!
先化简再求值
先化简再求值:4分之1x²y+3分之1x²y+3[-(9分之1x²y+xy)]+4分之3x²y,其中x=-1,Y=1.求解……很着急!
先化简再求值先化简再求值:4分之1x²y+3分之1x²y+3[-(9分之1x²y+xy)]+4分之3x²y,其中x=-1,Y=1.求解……很着急!
等于-2吧
=(1/4+1/3-1/3+2/4)x²y+3xy
=x²y+3xy
=(x+3)xy
x=-1,y=1代入
原式=(-1+3)*-1*1=-2
4分之1x²y+3分之1x²y+3[-(9分之1x²y+xy)]+4分之3x²y
=1/4x²y+1/3x²y-1/3x²y+3xy+3/4x²y
=x²y+3xy
其中x=-1,Y=1
上式=(-1)²*1+3*(-1)*1
=1-3
=-2
4分之1x²y+3分之1x²y+3[-(9分之1x²y+xy)]+4分之3x²y
=xy[x+3]
当x=-1,Y=1时,
xy[x+3]
=-2
原式=X2y+3xy,将x=-1,y=1代入得-2