# How do you solve \frac { 4} { d + 8} = \frac { 7} { d - 18}?

Nov 25, 2017

$d = - \frac{128}{3} \cong - 42.667$

#### Explanation:

We multiply in both sides by $\left(d + 8\right) \left(d - 18\right)$ so we end up with:
$\left(d - 18\right) 4 = 7 \left(d + 8\right)$

we multiply,
$4 d - 72 = 7 d + 56$

we isolate $d$,
$4 d - 7 d = 56 + 72$

$- 3 d = 128$

$d = - \frac{128}{3}$