Of the 120 rooms in a hotel, 55% are single bed rooms, 30% are double bed rooms and the rest are deluxe rooms. how many deluxe rooms are there

given the equation is 8+9z=-6, the first step would be to subtract the 8 from both sides:

8+9z-8=-6-8

since 8 minus 8 = 0, this would cancel out the 8. and since -6 minus 8 equals -14, the equation would look like this

9z = -14