Question

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Answer 1

4/x = b - x
4/(3 - √5) = b - (3 - √5)
b = 4/(3 - √5) + (3 - √5)
b = [4 + (3 - √5)^2] / (3 - √5) = [4 + 9 - 6√5 + 5]/(3 - √5) = (18 - 6√5) / (3 - √5) = 
= 6*(3 - √5) / (3 - √5) = 6