（5%-i)*( 100-108.11)=(5%-4% )*(100-104)（5%-i)=(5%-4% )*(100-104)/( 100-108.11)i=5%-(5%-4% )*(100-104)/( 100-108.11)=5%-1%*（-4）/（-8.11）=4.51% 这道题到了后面=5%-10%*（-4）/（-8.11）就不懂怎么算了，老师能一步步列等式出来吗？