mohon dijawab dengan caranya...

buku=×
pensil=y
penghapus=c

1x+2y+1c=15.000 ×1=1x+2y+1c=15000
1×+1y+1c=9000 ×2=2x+2y+1c=18000
- =-1x=-3000
=×=3000
subtitusi y

1x+2y+1c=15000
1(3000)+2y+1c=15000
3000+2y+1c=15000
2y+1c=15000-3000
2y+c=12000:1
2y=12000
y=6000
subtitusi c

1×+1y+1c=9000
1(3000)+1(6000)+1c=9000
9000+1c=9000
1c=9000+9000
1c=18000
c=18000

5×+5y+3c
5(3000)+5(6000)+3(18000)
15000+30000+24000
69000

maaf kalau salahh