a) 3-6x+8=32 <=>-6x=32-8-3<=>6x=21=>x=21 supra 6 ;
b)20x+30=12<=>20x=12-30=-18<=>x=-18 supra 20=-9 supra zece =>x=-9 supra zece
c)1-24x+12=1<=>-24x=1-12-1=-12<=>x=-12 supra 24=-1 supra 2=>x=-1 supra 2
d)1605 + 12-4x=2011 <=>-4x=2011-12-1605=39<=>x=-394 supra 4=-197 supra 2 =>x=-197 supra 2