notez c=creion si p=pix
5c+3p=19⇒3p=19-5c⇒p=(19-5c)/3
3c+6p=24. am aflat mai sus ca p=(19-5c)/3 inlocuim
3c+6×(19-5c)/3=24 acum 6 cu 3 se simplifica
3c+2×(19-5c)=24
3c+38-10c=24
38-24=-3c+10c
14=7c⇒c=14:7⇒c=2 deci un creion costa 2 lei
5c+3p=19
dar c=2
5×2+3p=19
10+3p=19
3-=19-10
3p=9⇒p=9:3⇒p=3 deci un pix costa 3 lei
verificare
5c+3p=?
5×2+3×3=10+9=19
3c+6p=?
3×2+6×3=6+18=24
va fi o problema daca nu ai invatat fractiile..nu m-am uitat sa vad in ce clasa esti
