1) (m+4)*(m-4)
2) (5n-p)*(5n+p)
3) (12a+7b)*(12a-7b)
4) (10x^2-y^2)*(10x^4+y^2)

1)(m+4)(m-4)=m^2-4^2=m^2-162)(5n-p)(5n+p)=(5n)^2-p^2=25n^2-p^23)(12a+7b)(12a-7b)=(12a)^2-(7b)^2=144a^2-49b^2