Left side of this equation is f(g(x)) = g(x) + 2 = x^2 + 2. Right side of this equation is g(f(x)) = (f(x))^2 = (x+2)^2 = x^2 + 4x + 4. So, this equation f(g(x))=g(f(x)) takes the form x^2 + 2 = x^2 + 4x + 4. Cancel the terms x^2 in both sides; keep the term with x in right side; collect constant terms in left side 2 - 4 = 4x -2 = 4x -1/2 = x. ANSWER. x = -1/2.