Find the domain of the function
`f(x)=(x^2+3x+5)/(x^2-5x+4)`

Explanation

Since `x^2-5 x+4=(x-4)dot(x-1)`, the function `f(x)` is defined for all real numbers except at `x=4` and `x=1`. Hence the domain of `f` is `R-1,4`