[2m/(m+4)+16/(m²-4m+16)-(m³-20m²)/(m³+64) ] × [ m+4 - 12m/(m+4)] =
= [ 2m/(m+4) + 16/(m²-4m+16) - (m³-20m²)/(m+4)(m²-4m+16) ] ×
× [ (m+4)(m+4)/(m+4) - 12m/(m+4) ] =
= [ (2m(m²-4m+16) + 16(m+4) - (m³-20m²))/(m+4)(m²-4m+16) ] ×
× [ (m+4)(m+4)/(m+4) - 12m/(m+4) ] =
= [ (2m³-8m²+32m + 16m+64 - m³+20m²)/(m+4)(m²-4m+16) ] ×
× [ (m²+8m+16 - 12m)/(m+4) ] =
= [ (m³+12m²+48m+64)/(m+4)(m²-4m+16) ] × [ (m²-4m+16)/(m+4) ] =
= [ ((12m²+48m) + (m³+64))/(m+4)(m²-4m+16) ] × [ (m²-4m+16)/(m+4) ] =
= [ (12m(m+4) + (m+4)(m²-4m+16))/(m+4)(m²-4m+16) ] ×
× [ (m²-4m+16)/(m+4) ] =
= [ ((m+4)(12m+m²-4m+16))/(m+4)(m²-4m+16) ] × [ (m²-4m+16)/(m+4) ] =
= [ ((m+4)(m²+8m+16))/(m+4)(m²-4m+16) ] × [ (m²-4m+16)/(m+4) ] =
= [ (m²+8m+16)/(m²-4m+16) ] × [ (m²-4m+16)/(m+4) ] =
= (m²+8m+16) / (m+4) = (m+4)² / (m+4) = m + 4