# How do you solve 15= - d + 20?

Sep 24, 2016

$d = 5$

#### Explanation:

Subtract $20$ from both sides. This gets us the equation

$15 - 20 = - d + 20 - 20$

$- 5 = - d$

You then can multiply both sides by $- 1$ to get

$- 5 \cdot \left(- 1\right) = - d \cdot \left(- 1\right)$

$5 = d$

The other way to do this is to add $d$ to both sides to get

$15 + d = 20$

and then subtract $15$ from both sides to get

$5 = d$

Either way, both of these work.