x+x(1+p1)+x(1+p1)(1+p2)+x(1+p1)(1+p2)(1+p3)=x+x(1+p)+x(1+p)^2+x(1+p)^3
1+p1+1+p1+p2+p1p2+1+p1+p2+p1p2+p3+p1p3+p2p3+p1p2p3=1+p+1+2p+p^2+1+3p+3p^2+p^3
3p1+2p2+p3+2p1p2+p1p3+p2p3+p1p2p3=6p+4p^2+p^3
3p1+2p2+m-p1-p2+2p1p2+(p1+p2)(m-p1-p2)+p1p2(m-p1-p2)=6p+4p^2+p^3看不懂啊。能简单解释下吗？？谢谢了。