令m=2/5 （因为2/5写起来太麻烦了,没有别的意思）a/b=m所以a=bm同理可得,c=dm,e=fm(1)（a-c)/(b-d) =(bm-dm)/(b-d)=m(b-d)/(b-d)=m=2/5(2)(2a+3c-4e)/(2b+3d-4f) =(2bm+3dm-4fm)/(2b+3d-4f)=m(2b+3d-4f)/(2b+3d-4f)=...