Let P(x) be a quadratic polynomial with complex coefficients whose x^{2} coefficient is 1 . Suppose the equation P(P(x))=0 has four distinct solutions, x=3,4, a, b. Find the sum of all possible values of (a+b)^{2}.
Let P(x) be a quadratic polynomial with complex coefficients whose x^{2} coefficient is 1 . Suppose the equation P(P(x))=0 has four distinct solutions, x=3,4, a, b. Find the sum of all possible values of (a+b)^{2}.