m^2(m-1)+(1-m)=m^2(m-1)-(m-1)
=(m-1)(m^2-1)
=(m+1)(m-1)^2
9-16(a-b)^2=3^2-[4(a-b)]^2
=[3+4(a-b)][3-4(a-b)]
=(4a-4b+3)(4b-4a+3)你确定？应该没错的……