yg baik tolong di jawab

Buku = a
Pensil = b

==Jawaban==
Dik:
3a + 2b = 11500
4a + 3b = 16000

Dit:
2a + b = ??????????

Jwb:
3a + 2b = 11500 (kalikan 3)
4a + 3b = 16000 (kalikan 2)
_________________________

9a + 6b = 34500
8a + 6b = 32000
________________________ -

a = 2500

Masukkan a ke:
3a + 2b = 11500
3(2500) + 2b = 11500
7500 + 2b = 11500
2b = 4000
b = 2000

Jadiiiiiii ↓↓↓↓↓↓
2a + b
= 2(2500) + 2000
= 5000 + 2000
= 7000 (C)