2. how many units of electriey would 150w refrigerator use in 24hour

The answer is b. (-13).

Use pythagorean’s theorem and find the missing side lengths of the two smaller triangles and add them together
13^2 - 12^2 = 5
15^2 - 12^2 = 9
5+9 = 14
14 is the length of each side of the square
14^2 + 14^2 = 19.8
19.8 is the diagonal length of the inside if the square

This is the same as saying x27y divided by 3. 27/3=9, so the expression can be simplified to 9xy