(m^2-2m)^2n+2n(m^2-2m)+n=n[(m^2-2m)^2+2(m^2-2m)+1]=n[(m^2-2m)+1]^2=n(m^2-2m+1)^2把(m^2-2m)看成一个整体就很好做了(x+y)^2-2x-2y+1=(x+y)^2-2(x+y)+1=[(x+y)-1]^2=(x+y-1)^2把x+y看成一个整体...