先化简再求值:3x²y-4xy²-3+5x²y+2xy²+5x=-1,y=2啊
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/06 19:45:06
![先化简再求值:3x²y-4xy²-3+5x²y+2xy²+5x=-1,y=2啊](/uploads/image/z/1977957-45-7.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%E5%86%8D%E6%B1%82%E5%80%BC%3A3x%26%23178%3By-4xy%26%23178%3B-3%2B5x%26%23178%3By%2B2xy%26%23178%3B%2B5x%3D-1%2Cy%3D2%E5%95%8A)
先化简再求值:3x²y-4xy²-3+5x²y+2xy²+5x=-1,y=2啊
先化简再求值:3x²y-4xy²-3+5x²y+2xy²+5
x=-1,y=2啊
先化简再求值:3x²y-4xy²-3+5x²y+2xy²+5x=-1,y=2啊
3x²y-4xy²-3+5x²y+2xy²+5
=(3x²y+5x²y)+(-4xy²+2xy²)+(-3+5)
=8x²y-2xy²+2
将x=-1,y=2代入上式
=8×(-1)²×2-2×(-1)×2²+2
=16+8+2
=26
答案:26