Given the system of equations 49x-14y+21z=40 14x+70y+28z=43 42x-14y-14z=11 What is x+y+z ? Answer: 3/2 This is a math competition question, and you are only given 1.5 minute to solve. You can solve x, y, z in a hard way, it will take long time and easyly make mistake. I think there might be a trick however I could not figure out. www.ddhw.com
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