Sort:  

3x=9
x+2y=5
y+2z=15
z+y+z=?
x=9/3=3
3+2y=5 \\\2y=2\\\y=1
1+2z=15\\\2z=14\\\z=7
x+y+z=1+3+7=11.

Coin Marketplace

STEEM 0.22
TRX 0.20
JST 0.034
BTC 98713.95
ETH 3352.77
USDT 1.00
SBD 3.07