Answer:
u = 5
Explanation:
The perimeter of a rectangle is all the sides added up.
The oppisite sides are parralel.
So the side across from 6 is all 6
6 + 6 = 12
The perimeter is 22 so you do
22 - 12 = 10
So 'u' equals 5 because you have to divide the number 10 by 2.