Question

I'm confused how to solve this, can someone help??

Answer 1

Hi, Mattie! :)

Follow BEDMASS. 
$-7=-1+x/3$
Add 1 to both sides.
$(-7)+1=(-1+x/3)+1$
$-6=x/3$
Multiply both sides by 3.
$(-6)*3=(x/3)*3$
$-18=x$

-18=x

Hope this helps.
-Benjamin

Answer 2

Add one on both sides of the equation. You would end up with -6=x/3. You would then cross multiply, so -6 times 3 and 1 (the denominator for -6) times x and you would get -18=x