Let f (x) = x2 + ax + B, a = {x | f (x) = x} = {a}, and the set composed of elements (a, b) be m

Let f (x) = x2 + ax + B, a = {x | f (x) = x} = {a}, and the set composed of elements (a, b) be m

∵ a = {x | f (x) = x} = {a}, the two equal roots of the equation x2 + ax + B = x are a. ∵ x2 + (A-1) x + B = 0, both are a. ∵ a + a = - (a − 1) a · a = B, ∵ a = 13b = 19, and the set of ∵ elements (a, b) is m, ∵ M = {(13, 19)}