Answer:
The correct expression for the perimeter is [tex]P=(\frac{5}{3}x+70)\ units[/tex]
see the explanation
Step-by-step explanation:
The complete question in the attached figure
Let
L ----> the length of rectangle
W ---> the width of rectangle
we know that
The perimeter of rectangle is equal to
[tex]P=2(L+W)[/tex]
In this problem we have
[tex]L=(\frac{5}{6}x+23)\ units[/tex]
[tex]W=12\ units[/tex]
substitute the values
[tex]P=2(\frac{5}{6}x+23+12)[/tex]
[tex]P=2(\frac{5}{6}x+35)[/tex]
[tex]P=(\frac{10}{6}x+70)\ units[/tex]
Simplify
[tex]P=(\frac{5}{3}x+70)\ units[/tex]
so
Michelle didn't multiply the sum of length and width by 2
