Question

-30=w+8 it's a equation

Answer 1

Yes, it's an equation.
Do you want the solution to this equation? for this we need to have w alone. So we need to get rid of 8:

-30-8=w+8-8

-38=w

inverting sides:
w=-38

Answer 2

$-30 = w + 8\\-30 -8 = w + 8 -8 \\ w = -30 - 8 \\ w = -1 (30+8)\\w = -1 (38)\\\\ \boxed{w=-38}$