Answer:
I would say 720
Step-by-step explanation:
one possibility that comes to my head is stack them on top of each other in many ways
<h3>Given</h3>
- room height is x feet
- room length is 3x feet
- room width is 3x feet
- a door 3 ft wide by 7 ft tall
<h3>Find</h3>
- The net area of the wall, excluding the door
<h3>Solution</h3>
The area of the wall, including the door, is the room perimeter multiplied by the height of the room. The room perimeter is the sum of the lengths of the four walls.
... gross wall area = (3x +3x +3x +3x)·x = 12x²
The area of the door is the product of its height and width.
... door area = (7 t)×(3 ft) = 21 ft²
Then the net wall area, exclusive of the door is ...
... net wall area = gross wall area - door area
... net wall area = 12x² -21 . . . . square feet
Answer:

Step-by-step explanation:
Let the number be x.
Translating the word problem into an algebraic equation, we have;
Opening the bracket, we have;

Collecting like terms, we have;

Answer:

Step-by-step explanation:
can be represented as
and
can be represented as
. Therefore, the expression can be rewritten as:

The rule for multiplying two exponents with the same base is you add the exponents. For example: 
We can use the same property to get:

which is just
after you add the fractions
Answer:
C . 5x-3y=-15
Step-by-step explanation: