E 4) In the diagram below, the dimensions of the large rectangle are (3x-1) by (3x+7) units. The dimensions of the cut-out rectangle are x by (2x+5) units. Which choice expresses the area of the shaded region, in Square units? ​

E 4 In the diagram below the dimensions of the large rectangle are 3x1 by 3x7 units The dimensions of the cutout rectangle are x by 2x5 units Which choice expre class=

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Answer:

Option (D)

Step-by-step explanation:

Area of a rectangle = Length × width

Area of large rectangle = (3x - 1)(3x + 7) square units

                                       = (9x² + 21x - 3x - 7)

                                       = 9x² + 18x - 7

Area of small rectangle = (2x + 5)x

                                       = (2x² + 5x) square units

Area of the shaded region = Area of large rectangle - Area of small rectangle

= (9x²+ 18x - 7) - (2x² + 5x)

= (9x² - 2x²) + (18x - 5x) - 7

= (7x² + 13x - 7) square units

Therefore, Option (D) will be the correct option.

The expression that represents the area of the shaded region is:[tex]7x\² + 13x - 7[/tex]

The dimension of the big rectangle is given as:

  • Length: 3x - 1
  • Width: 3x + 7

So, the area of the rectangle is:

[tex]Area = Length \times Width[/tex]

[tex]Area= (3x - 1) \times (3x + 7)[/tex]

Expand

[tex]Area = 9x\² + 21x - 3x - 7[/tex]

[tex]Area = 9x\² + 18x - 7[/tex]

The dimension of the small rectangle is given as:

  • Length: 2x + 5
  • Width: x

So, the area of the rectangle is:

[tex]Area = Length \times Width[/tex]

[tex]Area= (2x + 5) \times x[/tex]

Expand

[tex]Area = 2x\² + 5[/tex]

The area of the shaded region is the difference between the area of the big and small rectangles.

So, we have:

[tex]Area = (9x\²+ 18x - 7) - (2x\² + 5x)[/tex]

Expand, and collect like terms

[tex]Area = 9x\²- 2x\² + 18x -5x- 7[/tex]

[tex]Area = 7x\² + 13x - 7[/tex]

Hence, the area of the shaded region is [tex]7x\² + 13x - 7[/tex]

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