作业帮1.合并同类项 (9x²2xy+6)-[xy+7x²-2(-3y²-5)]+2y²-22.小能同学计算某多项式减去ab²-3bc-2c³d时,把“减去”看成了“加上”,得到的答案为-ab²-2c³d+3bc,请你求出这道题的正确结
来源：学生作业帮助网 编辑：作业帮 时间：2024/11/20 22:35:40
![1.合并同类项 (9x²2xy+6)-[xy+7x²-2(-3y²-5)]+2y²-22.小能同学计算某多项式减去ab²-3bc-2c³d时,把“减去”看成了“加上”,得到的答案为-ab²-2c³d+3bc,请你求出这道题的正确结](/uploads/image/z/1615306-58-6.jpg?t=1.%E5%90%88%E5%B9%B6%E5%90%8C%E7%B1%BB%E9%A1%B9+%289x%26%23178%3B2xy%2B6%29-%5Bxy%2B7x%26%23178%3B-2%28-3y%26%23178%3B-5%29%5D%2B2y%26%23178%3B-22.%E5%B0%8F%E8%83%BD%E5%90%8C%E5%AD%A6%E8%AE%A1%E7%AE%97%E6%9F%90%E5%A4%9A%E9%A1%B9%E5%BC%8F%E5%87%8F%E5%8E%BBab%26%23178%3B-3bc-2c%26%23179%3Bd%E6%97%B6%2C%E6%8A%8A%E2%80%9C%E5%87%8F%E5%8E%BB%E2%80%9D%E7%9C%8B%E6%88%90%E4%BA%86%E2%80%9C%E5%8A%A0%E4%B8%8A%E2%80%9D%2C%E5%BE%97%E5%88%B0%E7%9A%84%E7%AD%94%E6%A1%88%E4%B8%BA-ab%26%23178%3B-2c%26%23179%3Bd%2B3bc%2C%E8%AF%B7%E4%BD%A0%E6%B1%82%E5%87%BA%E8%BF%99%E9%81%93%E9%A2%98%E7%9A%84%E6%AD%A3%E7%A1%AE%E7%BB%93)
1.合并同类项 (9x²2xy+6)-[xy+7x²-2(-3y²-5)]+2y²-22.小能同学计算某多项式减去ab²-3bc-2c³d时,把“减去”看成了“加上”,得到的答案为-ab²-2c³d+3bc,请你求出这道题的正确结
1.合并同类项 (9x²2xy+6)-[xy+7x²-2(-3y²-5)]+2y²-2
2.小能同学计算某多项式减去ab²-3bc-2c³d时,把“减去”看成了“加上”,得到的答案为-ab²-2c³d+3bc,请你求出这道题的正确结果
1.合并同类项 (9x²2xy+6)-[xy+7x²-2(-3y²-5)]+2y²-22.小能同学计算某多项式减去ab²-3bc-2c³d时,把“减去”看成了“加上”,得到的答案为-ab²-2c³d+3bc,请你求出这道题的正确结
1解 (9x²+2xy+6)-[xy+7x²-2(-3y²-5)]+2y²-2
= (9x²+2xy+6)-[xy+7x²+6y²+10]+2y²-2
=9x²+2xy+6-xy-7x²-6y²-10+2y²-2
=2x²-4y²+xy-6
2原来的多项式为
-2ab²+6bc
故这道题的结果是
-2ab²+6bc-(ab²-3bc-2c³d)
=-3ab²+9bc+2c³d
(9x²-2xy+6)-[xy+7x²-2(-3y²-5)]+2y²-2
=9x²-2xy+6-xy-7x²+2(-3y²-5)+2y²-2
=9x²-2xy+6-xy-7x²-6y²-10+2y²-2
=2x²-3xy-4y²-6
全部展开
(9x²-2xy+6)-[xy+7x²-2(-3y²-5)]+2y²-2
=9x²-2xy+6-xy-7x²+2(-3y²-5)+2y²-2
=9x²-2xy+6-xy-7x²-6y²-10+2y²-2
=2x²-3xy-4y²-6
原多项式为：-ab²-2c³d+3bc -（ ab²-3bc-2c³d）=-2ab²+6bc
因而这道题的正确结果 -2ab²+6bc -（ab²-3bc-2c³d)
=-3ab²+9bc +2c³d
收起