What is the inverse transformation of T(x,y)=(x+3y,y)T(x, y) = (x + 3y, y)T(x,y)=(x+3y,y)?
T^{-1}(x, y) = (x - 3y, y)
T^{-1}(x, y) = (x + 3y, y)
T^{-1}(x, y) = (x - \frac{1}{3}y, y)
T^{-1}(x, y) = (x, y - 3x)