(5+m)(m-5)(m-5)(m+5)= (m^2-25)(m^2-25)= (m^2-25)^2
(m+5)^2(m-5)^2
(m^2+ 10m + 25)(m^2 - 10m+25)
m^4-10m^3+25m^2+10m^3-100m^2 + 250m+25m^2-250m+625
m^4-50m^2+625.
(5+m)(m-5)(m-5)(m+5)= (m^2-25)(m^2-25)= (m^2-25)^2
(m+5)^2(m-5)^2
(m^2+ 10m + 25)(m^2 - 10m+25)
m^4-10m^3+25m^2+10m^3-100m^2 + 250m+25m^2-250m+625
m^4-50m^2+625.