Domain of a function

Domain of the function $\frac{x}{\left(x^2+3x+2\right)}$ is 

• {- 1, - 2}

• R - {1, 2}

• R - {- 1, - 2}

• none of these

Find the domain of the function $f\left(x\right)=\frac{\left(x-2\right)}{x-3}$  

• {2, 3}

• R - {2}

• R - {3}

• none of these

Find the domain of  $f\left(x\right)=\frac{\left(x^2+1\right)}{\left(x^2-1\right)}$  

• R - {- 1, 1}

• R - {1}

• R - (- 1, 1)

• none of these

Domain of  $f\left(x\right)=\frac{1}{\sqrt{1-x}}$  is

•  $\left(-\infty,1\right)$  

•  $\left(1,\infty\right)$  

•  $R-\left\{1\right\}$  

• none of these

Domain of |x - 1| is

• {1}

• R

• R - {1}

• none of these

Domain of  $f\left(x\right)=\frac{x}{1+x^2}$ is 

• R

• R - {- 1, 1}

• R - {- 1}

• none of these

Domain of $f\left(x\right)=\frac{\left(x^2-25\right)}{x-5}$  is

• R

• R - {5}

• {5}

• none of these