Damian, word problems are only hard because of the need to translate words into math.
The first step is to name each of the quantities involved:
Let L be the length of the rectangle
Let W be the width
Next translate the words using these names:
Translate “the length is the width minus 5” into:
L = W - 5
I assume you know how to calculate Area...area = length * width.
Translate “the area is 24 units” into
L * W = 24
Now the problem is simply reduced to two equations, such as you’ve dealt with before. Does this help?