Bagaimana ini caranya saya ga paham. tolong bantuannya.

Misal, botol kecil=x, botol sedang=y. botol besar=z
x+2y=2100
2x+3z=5700
y+2z=3750

x+2y=2100 |×1
y+2z=3750 |×2

x+2y=2100
2y+4z=7500
__________ –
x-4z=-5400

x+2y=2100 |×2
2x+3z=5700|×1

2x+4y=4200
2x+3z=5700
__________ –
4y-3z=-1500

2x+3z=5700 |×1
x-4z=-5400 |×2

2x+3z=5700
2x-8z=-10800
___________ –
11z=16500
z=1500

y+2z=3750
y+2(1500)=3750
y+3000=3750
y=3750-3000=750

y+z=1500+750=2250