先化简,再求值;3(x²+1/3y)-2(3/2x²-xy)+(-y+3x),其中x=-2,y=1/2
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![先化简,再求值;3(x²+1/3y)-2(3/2x²-xy)+(-y+3x),其中x=-2,y=1/2](/uploads/image/z/1002755-11-5.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC%3B3%28x%26%23178%3B%2B1%2F3y%29-2%283%2F2x%26%23178%3B-xy%29%2B%28-y%2B3x%29%2C%E5%85%B6%E4%B8%ADx%3D-2%2Cy%3D1%2F2)
先化简,再求值;3(x²+1/3y)-2(3/2x²-xy)+(-y+3x),其中x=-2,y=1/2
先化简,再求值;3(x²+1/3y)-2(3/2x²-xy)+(-y+3x),其中x=-2,y=1/2
先化简,再求值;3(x²+1/3y)-2(3/2x²-xy)+(-y+3x),其中x=-2,y=1/2
3(x²+1/3y)-2(3/2x²-xy)+(-y+3x),
=3x²+y-3x²+2xy-y+3x
=2xy+3x
当x=-2,y=1/2时
原式=2×(-2)×1/2+3×(-2)=-2-6=-8