=(m^2-n^2)(-m^2-n^2)-(4m^2-n^2)(4m^2+n^2) =-(m^4-n^4)-(16m^4-n^4) =-（1^4-（-2)^4）-(16*1^4-(-2)^4)=15
答案是-(m^4-n^4)-(-16m^4+n^4)=15.
