Answer:
[tex](9x-1)\ units[/tex]
Step-by-step explanation:
we know that
The perimeter of a triangle is the sum of the length of their three sides
see the attached figure to better understand the problem
so
[tex]P=a+b+c[/tex]
where
a,b,c are the length sides of the triangle
In this problem we have
[tex]P=(16x+3)\ units[/tex]
[tex]a=(2x+5)\ units[/tex]
[tex]b=(5x-1)\ units[/tex]
substitute and solve for the missing length
[tex](16x+3)=(2x+5)+(5x-1)+c[/tex]
[tex]c=(16x+3)-(2x+5)-(5x-1)[/tex]
[tex]c=(9x-1)\ units[/tex]
