Ben, Cam, and Justin are lumberjacks. The number of trees they chop down is given by

where

is the number of hours Ben spends chopping,

is the number of hours Cam spends chopping, and

is the number of hours Justin spends chopping.
How many trees do they chop down after Ben spends

hours chopping, Cam spends

hours chopping, and Justin spends

hours chopping?
trees