Answer:
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The combined dimensions of the rectangle are:
- w = 3 + 2x and
- l = 8 + 2x,
since x is added to both ends.
The area of rectangle will be:
or
- f(x) = (3 + 2x)*(8 + 2x)
- f(x) = 3*8 + (3 + 8)(2x) + (2x)²
- f(x) = 24 + 22x + 4x²
- f(x) = 4x² + 22x + 24