y = (2/3)x - 1/3
y + 1/3 = (2/3)x
(3/2)*(y+1/3) = x
(3/2)y + 1/2 = x
f^-1(x) = (3/2)x + 1/2
This is the inverse you need to graph. You can plot this yourself, or use a graphing calculator.
The domain of f^-1(x) is all real numbers
The range of f^-1(x) is all real numbers
For the next 2, just plug in the values and solve:
f(2) = 1
f^-1(-19) = -28