(m-n)(m+n)(m2+n2)((2c+d)2-(c+2d)2)*3cd
1) (m–n)(m+n)(m^2+n^2)=(m^2-n^2)*(m^2+n^2)=m^4-n^4 2) ((2c+d)^2–(c+2d)^2)·3cd= =((2c+d)-(c+2d))*((2c+d)+(c+2d))*3cd= =(2c+d-c-2d)*(2c+d+c+2d)*3cd= =(c-d)*(3c+3d)*3cd=9cd*(c^2-d^2)