Răspuns :
x + y = 600
x - y = 120
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x + y + x - y = 600 + 120
2x = 720
x = 720 :2 =360
y = 600 - 360 = 240
x - y = 120
------------------------------
x + y + x - y = 600 + 120
2x = 720
x = 720 :2 =360
y = 600 - 360 = 240