4r+5c=62,80
5r+4c=63,20
fac in doua moduri pt ca nu stiu in ce clasa esti
I. 4r+5c=62,80=>4r=62,80-5c
r=(62,80-5c)/4
5r+4c=63,20
5× (62,80-5c)/4 +4c=63,20
314-25c+16c=252,8
-9c=-61,2
c=6,8 lei
r=(62,80-5×6,8)/4
r=(62,80-34)/4
r=28,8:4
r=7,2 lei
II. metoda cu sistem
{ 4r+5c=62,80 /×5
5r+4c=63,20 /×4
{ 20r+25c=314
20r+16c=252,8
------------------------(—)
9c=61,2
c=6,8 lei
{4r+5×6,8=62,80
c=6,8
{4r+34=62,80
c=6,8
{4r=28,8
c=6,8
{r=7,2
c=6,8
