решение- в приложении
1. 1/4m^2 - 16n^2=(1/2m-4n)(1/2m+4n)
2. x^12-y^2=(x^6-y)(x^6+y)
3. 1/4-c^4=(1/2-c^2)(1/2+c^2)
4. x^4-y^4=(x^2-y^2)(x^2+y^2)=(x-y)(x+y)(x^2+y^2)