Răspuns :

a-b=28

(a+b):28=13 rest 14
a+b=13x28+14
a+b=378

a-b=28⇒a=28+b
a+b=378

28+b+b=378
2b=378-28
2b=350
b=350:2
b=175

a=28+175
a=203

Verificare : 203+175=378
a - b = 28
( a+b ) : ( a - b ) = 13 rest 14
a + b = 13 x ( a - b ) + 14
a + b = 13 x 28 +14
a + b = 378
adunam cele doua relatii
a - b = 28
a + b = 378
--------------------
2a / = 406
a = 406 :2
a = 203

inlocuim in prima relatie
203 - b = 28
b = 203 - 28
b = 175