Question

-30-x=15 ...................

Answer 1

-30-x=15
-30+30-x=15+30
-x=45
$\frac{-x}{-1} = \frac{45}{-1}$
x=-45

Answer 2

-30-x=15
-x=15+30
-x=45
x=$-\frac{45}{1}$
x=-45