Answer: The mathematical formula would be
[tex](w+5)\times (w+2)-(w+5)(w)=28[/tex]
Step-by-step 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,
[tex]\text{Area of frame 2 - Area of frame 1}=28\\\\(w+5)\times (w+2)-(w+5)(w)=28\\\\(w^2+10+7w)-(w^2+5w)=28\\\\w^2+10+7w-w^2-5w=28\\\\2w+10=28\\\\2w=28-10\\\\2w=18\\\\w=\dfrac{18}{2}\\\\w=9[/tex]
Hence, the mathematical formula would be
[tex](w+5)\times (w+2)-(w+5)(w)=28[/tex]