Answer:
Step-by-step explanation:
You simply need to substitute the numbers in the x column into the equations in the topmost row. The answers are the values of a, b, c, d, e, and f.
Look at the filled in cells.
In the x column, we have -2, and the topmost row we have
. The answer is given as
. This is because 
Repeat this for the values that you need to find.
Area of ceiling: 6 x 5 = 30 square meters:
Area of 4 walls = 107 - 30 = 77 square meters
2 walls = 6 + 6 = 12 meters long
2 walls = 5 + 5 = 10 meters long
12 + 10 = 22
77 square meters / 22 meters = 3.5 meters
The walls are 3.5 meters high.
It looks like it is -1 chief