PLEASE HELP !! ILL GIVE BRAINLIEST *EXTRA 40 POINTS* DONT SKIP :(( .!

Answer: 12ft x 40ft
Step-by-step explanation:
We know that the perimeter is adding all of the sides.
We also know that our sides are as follows
Width=x
Length= 3x+4
We can add two of each (there are two length and two width on a rectangle) and we get
X + X + (3x+4) (3x+4)=104
Add like terms
8x + 8 =104
8x=96
Divide by 8 on both sides
X=12.
Again, the length is 3 times x plus 4.
Width= 12
Length= 40
12x40 feet