Question

Am nevoie de ajutor la aceste probleme:
1) a+b+c=108
a=b:3
c=5xa

2) ab=10
b(12-a)=50

Va rog sa ma ajutati si sa dati raspunsuri foarte bune!

Answer 1

a+bc=108
a=b:3,b=3a
c=5a
a+3a+5a=108
9a=108
a=108:9=12
b=3x12=36
c=5x12=60
12+36+60=108
2)ab=10
b(12-a)=50
12b-ab=50
12b-10=50
12b=50+10=60
b=60:12=5
a=10:5=2

Answer 2

$\rm \bold{Ex.~1} \\ a+b+c=108 \\ b:3=a\longrightarrow b=3a \\ c=5a \\ a+3a+5a=108 \\ 9a=108|:9 \\ \bold{a=12} \\ b=3\cdot12 \\ \bold{b=36} \\ c=5\cdot12 \\ \bold{c=60} \\ \\ \bold{Verificare:60+36+12=60+48=108} \\ \\ \\ \bold{Ex.~2} \\ ab=10 \\ b(12-a)=50 \\ Desfintam~paranteza: \\ 12b-ab=50 \\ 12b-10=50 \\ 12b=60|:12 \\ \bold{b=5} \\ 5a=10|:5 \\ \bold{a=2} \\ \\ \bold{Verificare:5(12-2)=5\cdot10=50}$