Răspuns :
P=2(L+l)
2(L+l)=76
L+l=76/2=38
L=38-l
2L+10=3(2l+10)
inlocuim in a 2-a.
2(38-l)+10=6l+30
76-2l+10=6l+30
66-2l=6l+30
6l+2l=66-30
8l=36
l=38/4=9,5
L=38-9,5=28,5
2(L+l)=76
L+l=76/2=38
L=38-l
2L+10=3(2l+10)
inlocuim in a 2-a.
2(38-l)+10=6l+30
76-2l+10=6l+30
66-2l=6l+30
6l+2l=66-30
8l=36
l=38/4=9,5
L=38-9,5=28,5