已知，a+b=4n+2，ab=1，若19a2+147ab+19b2的值为2009，则n=（ ）。
2或-3
An analyst gathered the following information: Taxable security, quoted yield 9.8% Tax-exempt security, quoted yield5.7% Investor’s marginal tax rate 35% For the tax-exempt security, the investor’s tax-equivalent yield is closest to（）
A. 5.7%
B. 8.8%
C. 10.7%
压缩天然气卸（装）车操作的安全技术规程是什麽？
