Răspuns :
LA prima imultesti cu -2 iar la a doua cu 3 si reduci x apoi afli pe y ;) nafta
x+2y-3z=5;3x-y+4z=1;2z-y+2z=0.(b)4x-y+2z=5;x+3y-z=4;15x+6y+3z=11.(c)2x+y-3z+t-0;x-y+4z=1;x+3y-2t=-1;3x+2y-z+2t=6.