Question

aflati dimensiunile unui dreptunghi stiind ca are perimetrul de 26 cm si aria de 40 cm patrati !

Answer 1

P=2(L+l)=26 => L+l=13 => L=13-l
A=L*l=40 => (13-l)*l=40 => 13*l-l*l-40=0 (inmultim cu -1) => l*l-13 l+40=0
=> D=169-4*40=169-160=9
l1=(13+9)/2=22/2=11
l2=(13-9)/2=4/2=2
L1=13-11=2
L2=13-2=11
Deci solutia finala este L=11, l=2