solve:
-60|x-11|+962 = 722
-60|x-11| = -240
|x-11| = 4
x-11 = 4 or -x+11 = 4
x =15 or x = 7
so either in 1995 or 1987
check:
http://www.wolframalpha.com/input/?i=-60%7Cx-11%7C%2B962+%3D+722
Amtrak's annual passenger revenue for the years
1985-1995 is modeled approximately by the formula
R=-60|x-11|+962
where R is the annual revenue in millions of dollars and
x is the number of years after 1980. In what year was the passenger revenue $722 million?
1 answer