# How do you simplify and find the excluded value of (d+7)/(d^2-49)?

Oct 1, 2016

$\frac{1}{d - 7}$ and $d \ne \pm 7$

#### Explanation:

The first approach with algebraic fractions is to see if you can find factors.

$\frac{d + 7}{{d}^{2} - 49} \text{ } \leftarrow$ difference of squares

$= \frac{\left(d + 7\right)}{\left(d + 7\right) \left(d - 7\right)} \text{ } \leftarrow d \ne \pm 7$

cancel((d+7))/(cancel((d+7))(d-7)

$= \frac{1}{d - 7}$