I have read that: In 1915 Einstein presents to the Prussian Academy of Sciences the General Theory of Relativity; it includes a set of Gravitational Field Equations; at this time he does not present any solution to the equations. In 1917 he considers a greatly simplified case; presents a solution and adds the cosmological constant to give a solution which yields a static universe. My question: Where do the following results come from, did he have to solve the equations to conclude the following? 1) The correct prediction of the amount of precession of the orbit of Mercury. 2) The correct prediction of the amount of bending of light by matter. 3) Time passes more slowly in a gravitational field.