2(㎡n+mn2)-3(㎡n-3)-2mn2-1其中m=-2n=2_数学解答

2(㎡n+mn2)-3(㎡n-3)-2mn2-1其中m=-2n=2

人气：279 ℃　时间：2020-06-20 12:44:50

解答

2(m²n+mn²)-3(m²n-3)-2mn²-1
=2m²n+2mn²-3m²n+9-2mn²-1
=-m²n+8
=-(-2)²×2+8
=-8+8
=0