Answer:
The student incorrectly simplified
.
Thus, option D is correct.
<u></u>
Step-by-step explanation:
The formula to determine the Perimeter of a rectangle of width w and length l is expressed as:

In other words, the perimeter can be determined by multiplying the length and width by 2 and adding the result.
In our case, the dimensions of a rectangle are
and
.
Here is the student's solution:


The student made an error in calculating
, because
are not like terms.
Hence,
can not be simplified to 
Therefore, the student incorrectly simplified
.
Thus, option D is correct.
<u></u>
<u></u>
<u>Here is the correct Solution:</u>

