a) 4:(4500:100+90:2-90)= 4:(45+45-90)= 4:0 imposibil
b)20x[5+10x(6+8:2)]:105=20x[5+10x(6+4)]:105=20x(5+10x10):105=
=20x105:105=20
c)1000735:5x[6-2x(4-1)]=200147x(6-2x3)=200147x0=0
d)478954:[10-5x(4x7-2x3)]
=478954:[10-5x(28-6)]
=478954:(10-5x22)
=
=478954:(10-110)
=478954:(-100)
=-4789,54