Answer:
The area of the frame is [tex](8x+16)\ ft^{2}[/tex]
Step-by-step explanation:
we know that
The area of the frame is equal to the area of the larger rectangle minus the area of the smaller rectangle
so
[tex]A=(x+5)(x+3)-(x+1)(x-1)\\A=(x^{2}+3x+5x+15)-(x^{2} -1)\\A= (x^{2}+8x+15)-(x^{2} -1)\\A=(8x+16)\ ft^{2}[/tex]