△=(m-2)²-4(0.5m-2) =m²-4m+4-2m+8 =m²-6m+12你怎么算出来的

△=(m-2)²-4(0.5m-2) =m²-4m+4-2m+8 =m²-6m+12你怎么算出来的

哪里不懂
a=1,b=m-2,c=0.5m-2
所以△=b²-4ac=(m-2)²-4(0.5m-2)
后面会了吧