The domain is the possible input values "x" .. in this case [-4, -2, 0, 2, 4]
The range are the possible output values of f(x)
We need to solve f(x) = 3.2x for each value in our domain
f(-4) = 3.2(-4) = -12.8
f(-2) = 3.2(-2) = -6.4
f(0) = 3.2(0) = 0
f(2) = 3.2(2) = 6.4
f(4) = 3.2(4) = 12.8
