Add the two equations together to get: (x+y) + 2xy = 17x+y = 17 - 2xy

Also multiply the two equations together to get: (x+xy) * (y+xy) = 72xy + (x+y)*xy + (xy)^2 = 72

Substitute my first equation into the second to get: xy + (17 - 2xy)*xy + (xy)^2 = 7218xy - (xy)^2 = 72(xy)^2 - 18xy + 72 = 0(xy - 6) * (xy - 12) = 0xy = 6 or 12

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