I am doing some homework on the golden ratio, and I'm told that the short side (b) is 10, and I am now trying to calculate side a... I have this so far http://mathbin.net/149853 and should get a when trowing it through the formula for quadratic equation, but what I get for a does not ad up to 0 when calculating what I have shown in the links... I have been staring at this for hours now. Please help :)

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