Răspuns :
720-s=r(r=s-136)720=s+r
720=s+s-136
2s=720+136
s=428
r=428-136
verif.720-428=428-136
720=s+s-136
2s=720+136
s=428
r=428-136
verif.720-428=428-136
D-S=r (1)
r=S-136 (2)
Inlocuiesc (2) in 1 si D=720
720-S=S-136 ⇒ 720+136= 856=2S
S= 856:2=428
r=428-136=292
r=S-136 (2)
Inlocuiesc (2) in 1 si D=720
720-S=S-136 ⇒ 720+136= 856=2S
S= 856:2=428
r=428-136=292