$29 dollars is the overall change in his account. The reason that this is correct is because if you make a number line -4 is exactly 29 units away from 25.
20. $158, 400 - multiply 40 by 22 to get the total square footage(880), then multiply 880 by 15 to get they total for the month, which is 13,200. lastly, you take 13,200 multiplied by 12(for each month in a year), and you get $157,400.
You know each side is 9 meters long, meaning it’s a square. To find perimeter, add up all the sides aka. 9+9+9+9=36. To find the area, multiply one side by the other aka. 9x9 = 81.