The life expectancy $y$ for females born in the United States is given by the equation $y=0.16 x+71.6,$ where $x$ is the number of years after $1950 .$ (Source: U.S. National Center for Health Statistics
a. Find the life expectancy of an American female born in 1980
b. Find and interpret the slope of the equation.
c. Find and interpret the $y$ -intercept of the equation.