Explicație pas cu pas:
X:{1000+100x[10+(25-x):5]}:400=6
X:[1000+100x(10+25-x:5)]:400=6
X:[1000+100x(10+5-x)]:400=6
X:(1000+100x (15-x):400=6
X:(1000+1500-100x):400=6
X:(2500-100x):400=6
X:2400x:400=6
X:2400x=400x6
X:2400=2400
X=2400:2400
X=1
Sper sa fie bine