Let u and v be the solutions to 3x^2 + 5x + 7 = 2x^2 - 4x - 11. Find u/v + v/u.
First combine like terms:
x^2 + 9x + 18 = 0 -> (x + 6)(x + 3) = 0.
Either x + 6 or x + 3 = 0 (not both), so x = -6 and x = -3.
If -6 and -3 are the values of u and v, plugging in we have u/v + v/u, -6/-3 + -3/-6 = 2 + 1/2 = 2.5