Răspuns :
a/3=b/4 =k
a/3 =k ; a=3k
b/4 =k ; b =4k
3a+b =39
3*3k+4k =39
9k+4k =39
13k =39
k =3
a=3k =3*3 =9
b=4k =4*3 =12
v ; 3*9+12 =27+12 =39
a/3 =k ; a=3k
b/4 =k ; b =4k
3a+b =39
3*3k+4k =39
9k+4k =39
13k =39
k =3
a=3k =3*3 =9
b=4k =4*3 =12
v ; 3*9+12 =27+12 =39