Răspuns:
a= 28.8 ; b= -3.2 ; c= 34.4
Explicație pas cu pas:
(a+b):2=12,8
(b+c):2=15,6
a+b+c=60
---------------/---
a,b,c=?
-------------//---
(a+b):2=12,8⇒a+b=2*12,8
a+b=25,6⇒a+b+c=60
25,6+c=60⇒c=34.4⇒
⇒b+c=b+34.4
(b+34.4):2=15.6
b+34.4=31.2⇒b= -3.2⇒a+b+c=a+-3.2+34.4⇒
⇒a+31.2=60⇒a=28.8
R: a= 28.8
b= -3.2
c= 34.4