1) 5(m-n)(m-n) = 5(m-n)^2 = 5(m^2 -2mn+n^2) = 5m^2 - 10mn+ 5n^2;
2) 2(m-n)(m-n) = 2(m-n)^2 = 2(m^2 -2mn+n^2) = 2m^2 - 4mn+ 2n^2.
1) 5(m-n)(m-n) = 5(m-n)^2 = 5(m^2 -2mn+n^2) = 5m^2 - 10mn+ 5n^2;
2) 2(m-n)(m-n) = 2(m-n)^2 = 2(m^2 -2mn+n^2) = 2m^2 - 4mn+ 2n^2.