The number of country A forces in country B decreased to approximately 34,000 in 2014 from a high of about 100,000 in 2008. The amount of country A funding for country B security forces
also decreased during this period. The function f(x) = - 1.339x² + 5.168x+5.517 can be used to
estimate the amount of country A funding for country B security forces, in billions of dollars, X
years after January 2007. In what year was the amount of country A funding for country B
security forces about $10.5 billion?