I am not sure about the answer, but the formula of the prism is LxWxH
Answer:

Step-by-step explanation:
The formula of an area of a rectangle:

l - length
w - width
We have

Substitute:
<em>divide both sides by 15</em>

The formula of a perimeter of a rectangle:

Substitute:

3x-6=6(x+2)
3x-6=6x+12 3x-6x=6+12
-3x=18 X= 18/-3 X= -6 first number .
For second number you substitute x+2.
-6+2=-4
The answer to 9+10 is 19 because if you add 9 to the number 10, you get 19