Question 680090
x+3y=12 
xy=9 --> y = 9/x
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sub for y in the 1st eqn
x + 27/x = 12
{{{x^2 - 12x + 27 = 0}}}
(x-3)*(x-9) = 0
x = 3, y = 3
x = 9, y = 1