由 5m²-3m -5=0 得 5(m²-1)=3m （m²-1）/m =3/5=0.6
所以 1/(5m²-2m -5)=1/(3m-m) = 1/m
5m²-2m = 5m²-5-2m+5 =m+5
5㎡-2m-[1/(5㎡-2m-5)]= m+5-1/m =m²-1）/m +5 =5.6
如5㎡-3m-5=0,求5㎡-2m-[1/(5㎡-2m-5)]=
由 5m²-3m -5=0 得 5(m²-1)=3m （m²-1）/m =3/5=0.6
所以 1/(5m²-2m -5)=1/(3m-m) = 1/m
5m²-2m = 5m²-5-2m+5 =m+5
5㎡-2m-[1/(5㎡-2m-5)]= m+5-1/m =m²-1）/m +5 =5.6