Answer: The mathematical formula would be

Explanation:
Let the width of the frame 1 be 'w'.
Let the width of the frame 2 be 'w+2'.
Let the length of frame 1 be 'w+5'.
Let the length of frame 2 be 'w+5'.
Since the area of frame 2 is 28 square inches more than the area of frame 1.
According to question, it becomes,

Hence, the mathematical formula would be
