Х-319=200 х+403=604 178-z=85 365+y=900

1
X=319+200
X=519

2
X=604-403
X=201

3
Z=178-85
Z=93

4
Y=900-365
Y=535

1) х - 319 = 200, х = 200 + 319, х = 519; 2) x + 403 = 604, x = 604 - 403, x = 201; 3) 178 - z = 85, z = 178 - 85, z = 93; 4) 365 + y = 900, y = 900 - 365, y = 535.