The expression used for the length of ribbon that she needs for both pillows will be [tex]4(2x^{2} +4x-6)[/tex].
The total length of the pillow she needs will be 130 inches.
Given,
The side length of pillow is [tex](2x^2 + 1) \ inches[/tex].
The side length of another pillow is [tex]4x-7 \ inches[/tex].
We know that perimeter of square will be,
[tex]P=4\times length[/tex]
So the perimeter of pillow will be,
[tex]P=4\times (2x^2+1)\\[/tex]
[tex]P=8x^{2} +4[/tex]
Similarly, the perimeter of another pillow will be,
[tex]P=4\times (4x-7)[/tex]]
[tex]P=16x-28[/tex]
Hence,the total length of ribbon that she needs for both the pillows will be,
[tex]8x^{2} +4+16x-28\\8x^{2} +16x-24\\4(2x^{2} +4x-6)[/tex]
If [tex]x=3.5\\[/tex] then the total length of ribbon will be,
[tex]4(2\times 3.5^{2}+4\times 3.5-6)\\4(2\times 12.25+14-6)\\[/tex]
[tex]4(24.5+8)[/tex]
[tex]4\times 32.5\\[/tex]
[tex]130 \ inches[/tex].
Thus the required expression will be [tex]4(2x^{2} +4x-6)[/tex] and the total length of ribbon she needs will be 130 inches.
So, the correct option will be (D).
For more details on perimeter of square follow the link:
https://brainly.com/question/5402168