#### Answer

$a + 2b$

#### Work Step by Step

We begin by distributing:
$-(a+2b)+4(a+2b)-2(a+2b)$
=$-a-2b+4a+8b-2a-4b$
Then we simplify by combining like terms. To combine like terms, simply add the coefficients of like variables:
$-a-2b+4a+8b-2a-4b$
=$a + 2b$