Determine the equation of the inverese of the quadratic function

f(x)=x^2-4x+3

x = y^2 - 4y + 3

y^2 - 4y = x-3

y^2 - 4 y + 4 = x+1

(y-2)^2 = x+1

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