*Perimeter *rectangle
IT is polynomials. Can you plz go step by step

I think it is 11.2 I solved it by trying to get the missing variable of the white rectangle then adding them together and I did that by this equation
2x+3=4x-5+x
2x+3= 5x-5
2x+8=5x
8=3x
so the missing side is 2.6