Ola Jose

y = (2x + 1)/(x - 3)

xy - 3y = 2x + 1

xy - 2x = 3y + 1

x*(y - 2) = 3y + 1

x = (3y + 1)/(y - 2)

f^-1(x) = (3x + 1)/(x - 2)

B) D(f^-1(x)) = R - {2}

pronto