All the values that will ever appear on the 'x + 1' side are on the straight green line, the line of Arithmetic Proportion.
All the values that will ever appear on the 'x * x' side are on the curved red line, the line of Geometric Proportion.
Only a value that's on both lines can satisfy both sides of the equation, so only such a value can be phi.
But what is its value, exactly, and why are there two???