Answer
x = 6
y = 0
Work Step by Step
x + y = 6 first equation
x - y = 6 second equation
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2x = 12 add the equations to eleminate y
x = 6 divide both sides by 2
let x = 6 in first equaton
x + y = 6
6 + y = 6
y = 0 subtract 6from both sides