Question

demonstrati ca, daca ab = 3* cd, atunci nr nat abcd se divide cu 7
PS: toate literele au linia aia deasupra​

Answer 1

abcd=ab•100+cd

daca ab=3•cd

=>abcd=3•100•cd+cd=301cd

abcd=301cd=7•43•cd

deci, abcd este divizibil cu 7; (daca ab=3·cd)