Find X : Y : Z If X - 2Y - Z = 0 and X + Y = 0

Solution:
Given

Again
X + Y = 0
Multiply by 2 on both side

Adding equation (1) and (2)

Therefore X=1 , Z=3
Now putting X=1, Z=3 in equation (1)
X - 2Y = Z
1 - 2Y = 3
2Y = 4
Y = 4/2
Y = 2
Therefore X : Y : Z = 1 : 2 : 3