Preheat oven to 400 degrees. Line a large jelly roll pan with aluminum foil. In a large bowl, mix the olive oil, broth, salt, and pepper and then toss with the mixed vegetables to coat. Drain and save the remaining broth mixture, then spread the vegetables on the jelly roll pan. Pour the reserved broth mixture over the vegetables. Roast for 35 to 40 minutes or until tender, stirring once.