# How do you simplify 2m - [n - (m - 2n)]?

Apr 11, 2018

$3 m - 3 n$

#### Explanation:

Expand the curly brackets first

$2 m - \left[n - m + 2 n\right]$
$2 m - \left[3 n - m\right]$
Then expand the square brackets

$2 m - 3 n + m$
$3 m - 3 n$

Apr 11, 2018

$3 m - 3 n$

#### Explanation:

You start by getting rid of the brackets inside the other brackets

$2 m - \left(n - m + 2 n\right)$

The $+$ became a $-$ because there was another $-$ in front. Now you remove the other bracket

$2 m - n + m - 2 n$

$3 m - 3 n$

and if you like you can write this as a common factor

$3 \left(m - n\right)$

The main thing is to understand that the signs alter as shown before.