Răspuns :
(ax3+2000)-3999-101=900/+101
(ax3+2000)-3999=1001/+3999
(ax3+2000)=5000/-2000
ax3=3000/3
a=1000
(ax3+2000)-3999=1001/+3999
(ax3+2000)=5000/-2000
ax3=3000/3
a=1000
{[(a+2a)+2000]-3999}-101=900
[(a+2a)+2000]-3999=1001
(a+2a)+2000=5000
3a+2000=5000
3a=3000
a=3000:3
a=1000
[(a+2a)+2000]-3999=1001
(a+2a)+2000=5000
3a+2000=5000
3a=3000
a=3000:3
a=1000