Answer:
[tex](9x-5)\ units[/tex]
Step-by-step explanation:
The picture of the question in the attached figure
we know that
The perimeter of a triangle is the sum of the length of their three sides
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-6)\ units\\a=(2x-5)\ units\\b=(5x+4)\ units[/tex]
substitute and solve for the missing length
[tex](16x-6)=(2x-5)+(5x+4)+c\\c=(16x-6)-(2x-5)-(5x+4)\\c=(9x-5)\ units[/tex]
