The equation y=-1777x + 27,153 can be used to predict the number y of gun deaths in the United States x years after 2000, that is, x=0 corresponds to 2000, x=3 corresponds to 2003, x=4 corresponds to 2004, and so on. Predict the number of gun deaths in 2004 and 2007. In what year will the number of gun deaths be 12,937?
Use the equation you were given and plug in 4 and 7 for x. See what numbers you get for y.
For the last part, solve the equation
12937= -1777x + 27,153
to obtain x.
These are certainly problems you can do yourself.