# What values of x are not in the domain of the expression (x+5)/(3x^2+23x-36)?

Mar 13, 2017

${D}_{f} \in R - \left\{9 , - \frac{4}{3}\right\}$

#### Explanation:

$\frac{x + 5}{3 {x}^{2} + 23 x - 36}$

The denominator should not be zero.

$3 {x}^{2} + 23 x - 36 \ne 0$

$3 {x}^{2} + 27 x - 4 x - 36 \ne 0$

$\left(x - 9\right) \left(3 x + 4\right) \ne 0$

$x \ne 9$ and $x \ne - \frac{4}{3}$

${D}_{f} \in R - \left\{9 , - \frac{4}{3}\right\}$