Question

The domain of the function $f\left(x\right)=\frac{x^2+3x+5}{x^2-5x+4}$ is

• A. $R$
• B. $R-\left\{1,4\right\}$
• C. $R-\left\{1\right\}$
• D. $(1,4)$

Answer 1

Answer: (B)

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