Let

'l' = the length of the rectangle

'w' = the width of the rectangle

A = w*l = the area of the rectangle

We need to find w.

l = 4 + w (length of a rectangle is 4 units more than width)

w*l = 25 + 4*w (area of the rectangle is 25 more than 4 times the width)

w*(4 + w) = 25 + 4*w

4*w + w^2 - 25 - 4*w = 0

w^2 = 25

w = 5 since the width needs to be non-negative number

The width of the rectangle is 5 units.