((³log36)² – (³log4)²) : (1+³log4) =

= ((³log9*4)² – (³log4)²) / (1+³log4)
= ((³log9 + ³log4)² – (³log4)²) / (1+³log4)
= ((2 + ³log4)² – (³log4)²) / (1+³log4)
= (4 + 4³log4 + ³log² 4 - ³log²4) / (1+³log4)
= (4 + 4³log4) / (1+³log4)
= 4(1+³log4) / (1+³log4)
= 4