If there is only one element a in the set a = {x x square + ax + B = x}, the values of a and B are obtained One more question Set u = {x, X is less than or equal to 10, X belongs to n}, a (symbol I can't play, that is, there is a U lying below with a horizontal) u, B (same as above) U So give 30 points to those who can answer all the questions One more question. A total of 40 points

If there is only one element a in the set a = {x x square + ax + B = x}, the values of a and B are obtained One more question Set u = {x, X is less than or equal to 10, X belongs to n}, a (symbol I can't play, that is, there is a U lying below with a horizontal) u, B (same as above) U So give 30 points to those who can answer all the questions One more question. A total of 40 points

1. If a = {x | x ^ 2 + ax + B = x} has only one element a, then the univariate quadratic equation x ^ 2 + (A-1) x + B = 0 has only one real root a, so Δ = (A-1) ^ 2-4b = 0, a ^ 2 + A (A-1) + B = 0, the solution is a = 1 / 3, B = 1 / 92. U = {x | x ≤ 10, X ∈ n} = {0,1,2,3,4,5,6,7,8,9,10} the problem is not complete, what do you want