WASHINGTON (AP) — Dozens of cities are working frantically to land Amazon's second headquarters, raising a weighty question with no easy answer: Is it worth it? Amazon is promising $5 billion of investment and 50,000 jobs over the next decade and a half. Yet the winning city would have to provide Amazon with generous tax breaks and other incentives that can erode a city's tax base. Most economists say the answer is a qualified yes — that an Amazon headquarters is a rare case in which a package of at least modest enticements could repay a city over time.