I think you just add all the sides even the ones you don't see. The left side of the shape is 6m as well as the right. and the same with the 4s. The answer is 36.
Remark
A cube has six sides, all of them equal. The formula for 1 side is s^2. The formula for all six = 6s^2.
Step One
Find the surface area of the larger cube.
Area = 6 *s^2
s = 15
Area = 6 *15^2
Area = 6 * 225
Area = 1350
Step Two
Find the area of the smaller cube
Area = 6s^2
Area = 6 * 12^2
Area = 6 * 144
Area = 864
Step Three
Find the difference
Area1 - Area2 = difference
1350 - 864 = 486
The difference is area = 486 units^2 <<<<< Answer
There is a slightly shorter way. Take out the common factor of 6
Difference = 6 * (15^2 - 12^2)
Difference = 6 * (225 - 144)
Difference = 6 * (81)
Difference = 486
Answer:
-8(8-7a)
Step-by-step explanation:
56a-64=-8(8-7a)