f(x) is the same as y.......so basically ur subbing in ur points into the equation to see if it comes out equal.
f(x) = 3 - 2x.....(-2,-1)....x = -2 and f(x) = -1
-1 = 3 - 2(-1)
-1 = 3 + 2
-1 = 5.....this is not true, so it is not a solution
and that is how to do this problem.....
(-1,5)......this IS a solution
(0,3)......this IS a solution
(1,0)...this IS NOT a solution
(2,-1)...this IS a solution
