▪Răspuns :
a + b + c = 1000
a + b = c
a - b = 200
a + b + c = 1000
c + c = 1000
2 × c = 1000
c = 1000 : 2
c = 500
a - b = 200
a = 200 + b
a + b = c
200 + b + b = 500
200 + 2b = 500
2 × b = 500 - 200
2 × b = 300
b = 300 : 2
b = 150
a + 150 = 500
a = 500 - 150
a = 350