A simple problem but im not too sure how to solve algebraically.

The length of a rec is seven more than twice it's width. If the perimeter of the rec is 50cm find the dimensions of the rec.

I just started out assuming the rec was in direct variation and worked from there.

50 = 2l + 2w
50/2 = 2l / 2 + 2w
25 = l
50/2 = 2w/2
25 = w

25 / 2 + 7 = 32 / 2 = 16cm
50 - 32 = 18/2 = 9cm

Now this should be the right answer but when i set this problem up im not sure what to do. 50cm = 2l + 2(2l + 7).