Răspuns :
120:X =13 rest 3
, se aplica teorema impartirii cu rest:
D:I=c, rest⇔I=(D-r):c
⇒Xx13=120-3
Xx13=117
X=117:13
X=9
120:9=13 rest 3
D:I=c, rest⇔I=(D-r):c
⇒Xx13=120-3
Xx13=117
X=117:13
X=9
120:9=13 rest 3
120:X=13r3
13xX+3=120
13xX=120-3
13xX=117
13xX=117:13
13xX=9
Proba:120:9=13r3
13xX+3=120
13xX=120-3
13xX=117
13xX=117:13
13xX=9
Proba:120:9=13r3