Răspuns :
a+b=53
a:b=9r3
a=9xb+3
a=9b+3
Inlocuim
9b+3+b=53
10b=53-3
10b=50
b=50:10
b=5
a=9b+3
a=9x5+3
a=45+3
a=48
a:b=9r3
a=9xb+3
a=9b+3
Inlocuim
9b+3+b=53
10b=53-3
10b=50
b=50:10
b=5
a=9b+3
a=9x5+3
a=45+3
a=48
a+b=53. a:b=9 rest 3. a=9b+3. 9b+3+b=53 <=> 10b+3=53 <=> 10b=53-3 <=> 10b=50 <=> b=50:10 <=> b=5. a=9•5+3 <=> a=48.