I have two questions which I have attempted to do with no success, can you thoroughly explain what to do?

The length of a swimming pool is 2.5m greater than its width. The pool's perimeter is 29m. Find the lenghth of the pool.

So, for this one. I knew that the perimeter is 2l + 2w

so I ended up with this 29 =2(2.5l(w))

then I don't know what to do after that.

correction ... P = 2(L + W)

P = 2[(2.5+W) + W]

P = 2(2.5 + 2W)

P = 5 + 4W
The second question is

Do I turn the mixed fraction into a improper one first then move 5x to the left hand side? then move 11/20 to right hand side so it would be: