Question

-7m²n²+2mn+6m²n²+（-2mn）+m²n²+3m²n+3mn．

Answer 1

分析：原式去括号合并即可得到结果．

解答：解：原式=（-7+6+1）m²n²+（2-2+3）mn+3m²n²
=3mn+3m²n．

点评：此题考查了整式的加减，熟练掌握运算法则是解本题的关键．