let’s say the length is x. That would mean that the width is 2x-2. 
using this we would have this equation: 
2x+ 2(2x-2) = 26
distribute 
2x+ 4x-4= 26
add like terms 
6x-4=30
add 4 to both sides
6x=30
divide
x= 5 
since x is our length, the length is 5
now for the width, use the 2x-2 equation and plug in x. you should get 8
l= 5
w=8
i hope this helps!!