Answer:
[tex] \mathsf{ {5x}^{2} + 28x + 21}[/tex]
Option A is the right option.
Step-by-step explanation:
Let's find the area of large rectangle:
[tex] \mathsf{(3x + 6)(2x + 4)}[/tex]
Multiply each term in the first parentheses by each term in the second parentheses
[tex] \mathsf{ = 3x(2x + 4) + 6(2x + 4)}[/tex]
Calculate the product
[tex] \mathsf{ = 6 {x}^{2} + 12x + 12x + 6 \times 4}[/tex]
Multiply the numbers
[tex] \mathsf{ = 6 {x}^{2} + 12x + 12x + 24}[/tex]
Collect like terms
[tex] \mathsf{ = {6x}^{2} + 24x + 24}[/tex]
Let's find the area of small rectangle
[tex] \mathsf{(x - 3)(x - 1)}[/tex]
Multiply each term in the first parentheses by each term in the second parentheses
[tex] \mathsf{ = x( x - 1) - 3(x - 1)}[/tex]
Calculate the product
[tex] \mathsf{ = {x}^{2} - x - 3x - 3 \times ( - 1)}[/tex]
Multiply the numbers
[tex] \mathsf{ = {x}^{2} - x - 3x + 3}[/tex]
Collect like terms
[tex] \mathsf{ = {x}^{2} - 4x + 3}[/tex]
Now, let's find the area of shaded region:
Area of large rectangle - Area of smaller rectangle
[tex] \mathsf{6 {x}^{2} + 24x + 24 - ( {x}^{2} - 4x + 3)}[/tex]
When there is a ( - ) in front of an expression in parentheses, change the sign of each term in the expression
[tex] \mathsf{ = {6x}^{2} + 24x + 24 - {x}^{2} + 4x - 3}[/tex]
Collect like terms
[tex] \mathsf{ = {5x}^{2} + 28x + 21}[/tex]
Hope I helped!
Best regards!
