Verified Answer :

Data:
Lenght (L)  = 5 + Width (W)
Perimeter = 50 ft
A (area) = ?

Solving: (Let's find the Widht value)

Perimeter = 2Lenght + 2Width

50 = 2(5 + W) + 2W
50 = 10 + 2W + 2W
2W + 2W = 50 - 10
4W = 40
\(W = \frac{40}{4}\)
\(\boxed{W = 10\:ft}\)

Now, let's find the length value:

Lenght (L)  = 5 + Width (W)
L = 5 + 10 
\(\boxed{L = 15\:ft}\)

Once you have found the length and width values, find the value of the rectangle area:

Formula \(A(area) = Lenght*Width\)

Solving:
\(A(area) = Lenght*Width\)
\(A(area) = 15*10\)
\(\boxed{\boxed{A = 150\:ft^2}}\end{array}}\qquad\quad\checkmark\)