mx-2(x- 1 3 y2)+(- 3 2 x+ 1 3 y2)=mx-2x+ 2 3 y2- 3 2 x+ 1 3 y2=(m- 7 2 )x+y2,因为将x=-2代入为x=2结果不变,所以可得x的系数为0,即m- 7 2 =0,解得:m= 7 2 .