#### Answer

Algebraic expression translation:
$8-3(x+6)$
Simplified form:
$-3x-10$

#### Work Step by Step

Let $x$ = the unknown number
Three times the sum of a number and six:
$3(x+6)$
Eight decreased by three times the sum of a number and
six
$8-3(x+6)$
Simplifying gives:
$=8-3(x)-3(6)
\\=8-3x-18
\\=-3x-10$