Question

Daca ai cumparat 3 caiete stundentesti, doua caiete matematica si doua carnetele-vocabular, ar trebui sa platesti la casa 26 de lei. Pentru doua caiete stundentesti, 4 caiete de matematica si un carnetel-vocabular, vanzatoarea iti va cere 25 de lei, iar daca vei cumpara 4 caiete stundentesti, doua de matematica si 3 carnetele-vocabular, va trebui sa scoti din buzunar 33 de lei. Afla pretul fiecarui articol. Va rog ajutatima urgent!!! Cu metoda comparartiei sa fie rozolvarea!!!

Answer 1

2s+4m+1c=25
3s+2m+2c=26
4s+2m+3c=33

2s+4m+1c=25
c=25-2s-4m

3s+2m+2c=26
3s+2m+2(25-2s-4m)=26
3s+2m+50-4s-8m=26
-1s-6m+50=26
-1s=6m+26-50
-1s=6m-24
s=-6m+24

4s+2m+3c=33
4(-6m+24)+2m+3(25-2(-6m+24)-4m)=33
-24-96+2m+3(25+12m-48-4m)=33
-24-96+2m+3(-23+8m)=33
-24-96+2m-69+24m=33
26m=33+24+96+69
26m=57+96+69
o sa continui in comentarii ca trebuie sa folosesc calculatorul si nu vreau sa se piarda ce am scris pana acum

Answer 2

3c.s....+2c.m...+2c.v...=26 lei
2c.s....+4c.m...+1c.v...=25 lei
4c.s....+2c.m...+3c.v...=33 lei
---------------------------------------
c.s=?; c.m=?; c.v=?

3cs+2cm+2cv=26lei+ (plus)
2cs+4cm+1cv=25lei
-----------------------------------
=5cs+6cm+3cv=51lei -(minus)
  4cs+2cm+3cv=33lei
-----------------------------------
=1cs+4cm+0cv=18lei...............=> .....1cs+4cm=18 lei


2cs+4cm+1cv=25lei -(minus)
1cs+4cm+ocv=18lei
----------------------------------------
=1cs.+0cm+1cv=7lei.................=>......1cs+1cv=7lei


3cs+2cm+2cv=26lei -(minus)
1cs+0cm+1cv=7 lei
-----------------------------------------
=2cs+2cm+1cv=19lei

2cs+4cm+1cv=25lei -(minus)
2cs+2cm+1cv=19lei
-----------------------------------------
=ocs+2cm+0cv=6lei..................=>2cm=6 lei...=>1cm.=6:2...=>1cm=3lei
                                                  =>1 caiet de matematica =3 lei

1cs+4cm=18lei
1cs+4cm*3=18lei
1cs+12lei=18lei
1cs=18-12
1cs=6lei.....................=>1 caiet studentesc= 6 lei

1cs+1cv=7lei
1cs*6+1cv=7lei
6lei+1cv=7lei
1cv=7-6
acv=1leu............=>1 carnetel vocabular =1 leu

verificare:

3cs*6lei+2cm*3lei+2cv+1leu=
=18lei+6lei+2lei
=24lei+2lei
=26lei

2cs*6lei+4cm*3lei+1cv*1leu=
=12lei+12lei+1leu
=24lei+1leu
=25lei

4cs*6lei+2cm*3lei+3cv*1leu=
=24lei+6lei+3lei
=30lei+3lei
=33lei