f(x) = (2x - 3) / (2x + 1)
y = (2x - 3) / (2x + 1) (express f(x) as y)
Switch x's and y's for inverse:
x = (2y - 3) / (2y + 1)
Solve for y:
x(2y + 1) = 2y - 3 (cross multiply)
2xy + x = 2y - 3 (distribute x on left side)
2xy + x - 2y = -3 (get rid of 2y on right side)
2xy - 2y = -x - 3 (get rid of x on left side)
y(2x - 2) = -x - 3 (factor out y on left side)
y(2x - 2) = -1(x + 3) (factor out -1 on right side)
y = (-1(x + 3)) / (2x - 2) (get rid of 2x - 2 on left side)
y = (-1(x + 3)) / (2(x -1)) (factor out 2 in denominator on left side)
Inverse Function (express y as f(x)):
f(x) = (-1(x + 3)) / (2(x - 1))
Domain is x not = 1, since x = 1 causes division by zero, which makes inverse function undefined.