Răspuns:
E(x) = x/x^2(x+1) • 6(x+1)(x-1)/(2x^2 + 3x - 2 - x^2 - 3x + 1)
E(x) = 1/x • 6(x-1)/(x^2 - 1)
E(x) = 6(x-1)/x(x+1)(x-1)
E(x) = 6/x(x+1)