What is its length?

Question

The perimiter of a rectangle is twice the sum and its length. The perimeter is 34 meters and its length is 2 meters than twice its width.

Answer 1

Your first sentence,
The perimiter of a rectangle is twice the sum and its length

is incoherent.

 

The perimeter (note spelling) of any rectangle is twice the sum of its length and width.  ⇐Corrected (definition).

 

In your second sentence, you give reasonable facts.  A third sentence ought to be present, such as

Find the length and width measures of this rectangle.

 

Now you have a problem that you should be able to solve.  Begin as follows:

P = 2(L + W) = 34

L = 2 + 2W

 

That's 2 equations with two unknowns.  Solve this system, and check answers.