10 .
P= 1436=2(L+l)
L= 2l+28
2(2l+28+l)=1436
3l=690
l=230cm
2L=2l=1436
2L+460=1436
2L=976
L=488 cm
14.
lungimea = latimea + 35m
Pdreptunghi=latimea +370
P=2xL + 2xl
370 + l = 2 x(l+35) + 2xl
370 = 2l-l + 2l+70
370-70=3l
300=3l
l=300:3
l=100 m L=l+35=100+35=135m
proba : P dreptunghi = 2xL+2xl=2x135+2x100=270+200=470
P dreptunghi= latimea +370=100+370=470