Răspuns :

Buna !

a+b+c=65

b=a+5

c=3a

a+b+c=65

a+a+5+3a=65

5a=65-5

5a=60

a=60 : 5

a=12

b= a + 5

b= 12 + 5

b= 17

c= 3 a

c= 3 x 12

c=36

verificare :

a+b+c=12 + 17+ 36= 65