Răspuns:
4kg.......12 lei
11kg......x lei
=> 11×12/4
=>132/4=33 lei.
x×3+11=3x+11
[(3x+11)÷4+6]:2=7
=> 7×2=14
14-6=8
8×4=32
32-11=21
3x=21=>x=7
P dreptunghi=500m
L=4l
=> Pdreptunghi= 2×(L+l)
=> 2×(4l+l)=500
=>2×5l=500
=>5l=250
=>l=250÷5
=>l= 50m
=>L=4×50=200m
=>Pdreptunghi= 2×(200+50)=> 2×250=500m
1. 3C+4c=800g /×(-2)
6C+2c=1300g
2. -6C+8=1600
6C+2c=1300
___________
/ 6c=300
=> c=300÷6
=>c=50
Inlocuim in prima relatie si avem => 3C+200=800
=>3C=600
=>C=200
