ajutor va rog!! Am nevoie URGENTT!!!!!

Răspuns:
(-2/3•1/2)²:1/9=-2/6²•9/1=-4/36•9/1= -36/36
1/4-(-1/2)²•-1²/2=1/4+2/4•(-1/2)=3/4•2/-1= 6/-4
(2/1-7/4+1/2)²-3²/4=(8/4-7/4+2/4)²-3²/4=(3/4)²-3²/4=9/16-9/4=9/16-36/16= -27/16
coroana?