1/3y=x

y+x+4=0

y + x + 4 = 0

x = 1/3 y

Substitute x = 1/3 y in,
y + x + 4 = 0

y + 1/3 y + 4 = 0
Multiply both sides by 3
3y + y + 12 = 0
4y = -12
y = -3

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