Răspuns :
700 + [400 - (x - 300) ] =850/-700
400-(x - 300) = 150/-400
x - 300 = 250 /+ 300 rezulta ca x= 550
400-(x - 300) = 150/-400
x - 300 = 250 /+ 300 rezulta ca x= 550
[400-(x-300)]=850-700
[400-(x-300)]= 150
x-300=400+150
x-300=550
x=550+300
x=850
[400-(x-300)]= 150
x-300=400+150
x-300=550
x=550+300
x=850