a,b=?
a) a+b=2929
a:b=103rest17 => a=103b+17
103b+17+b=2929
104b=2929-17
104b=2912 => b=2912:104 => b=28
a=103x28+17 => a=2884+17 => a=2901
verificam: 2901+28=2929
b) a-b=794
a:b=4rest83 => a=4b+83
4b+83-b=794
3b=794-83
3b=711 => b=711:3 => b=237
a=4x237+83 => a=948+83 => a=1031
verificam: 1031-237=794