Răspuns :
a + b = 431
2a + 5b = 1696
a = 431 - b
2(431 - b) + 5b = 1696
862 - 2b + 5b = 1696
862 + 3b = 1696
3b = 1696 - 862
3b = 834
b = 834 : 3
b = 278
a = 431 - 278 = 153
a + b = 431
2a + 5b = 1696
a = 431 - b
2(431 - b) + 5b = 1696
862 - 2b + 5b = 1696
862 + 3b = 1696
3b = 1696 - 862
3b = 834
b = 834 : 3
b = 278
a = 431 - 278 = 153