Rectangular Areas and Perimeters
The perimeter of a rectangle is given by:
In the problem we have these data:
- Perimeter = 6 + 2 (-2x + 20)
We replace the data in the equation of the perimeter:
6 + 2 (-2x + 20) = 2 (a - 2x + 20)
We apply distributive property:
6 - 4x + 40 = 2a - 4x + 40
6 = 2a
6 ÷ 2 = a
3 = a
⇒ Length = 3
The area of the rectangle is given by:
We have these data:
We replace the data in the equation of the area:
Area = (3) (- 2x + 20)
We apply the distributive property and obtain:
Area = -6x + 60
The expression representing the area of the rectangle will be -6x + 60
I hope I've helped!