Your friend Sam wants to paint her room. She wants to paint the ceiling white and the four walls purple.
You are helping Sam determine the cost and the amount of time needed to
paint her room.
The room is shaped like a rectangular prism with a height of 8 feet, length of
12 feet, and width of 10 feet as shown.

one hundred and twenty approximately

han when lo ahe whn hew anh ? ?

explanation:

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".