a + b+ c = 1758
a- 207= x rezulta a= 207+x
b- 68 = x rezulta b = 68 + x
c- 220= x rezulta c= 220 +x
a + b + c = 1758 a = 207+ x=207+421= 628
207+x+68+x+220+x = 1758 b= 68 + x = 68+ 421= 489
3x + 495 = 1758 c= 220 + x= 220+421= 641
3x = 1758 - 495
3x = 1263
x = 1263 :3 Raspuns : a = 628 ; b=489; c=641
x= 421