Question 1425
x = y + 3
y = 3 - x

x - y = 3
x + y = 3
Add the 2 equations.
2x    = 6
x = 3
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Now plug into the first equation to solve for y.
3 = 0 + 3.
y = 0
check in the second equation.
0 = 3 - 3.
This does check, 
Cleomenius.