Find the domain and range of the function: f(x)=(4/5) l8-xl
Domains are easy. What values of x does f(x) not exist? There are no restrictions here so the domain of the function is all real numbers.
Ranges are harder. When all else fails, graph it. In this case we can see that the minimum of the function is at x = 8. There is no upper bound. So the range is $\displaystyle [0, \infty ) $.
-Dan