The length of a rectangle is three times the width. The perimeter of the rectangle is 40 inches. What is the area of the rectangle (in square inches)

The length of the rectangle: 3x

The width of the rectangle: x

Theres 2 lengths and 2 widths for every rectangle.

So the full perimeter is 3x+x+3x+x = 8x

8x;

= perimeter

= 40 inches

8x=40

x=40/8

x=5 inches

Length is 3x, substitute in for x

l = 3(5)

l = 15

the first question mark is 6 and the second question mark is 26 (the square root)

step-by-step 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".