Question

The length of a rectangular sign is 3ft longer than the width. If the signs area is 54 square ft, find its length and width.

Answer 1

We don't know the length or the width, but we do know something about the length in terms of the width.
"The length of a rectangular sign is 3ft longer than the width."

This suggests we should pick a variable to represent the width.
Then we will write an expression for the length in terms of the width.

Answer 2

Let the width be w.
Since the length is 3 ft longer than the width, what is the length in terms of w?

Answer 3

The length is w + 3

Answer 4

Now use the length and width, w, and w + 3, to write an expression for the area.
Area of rectangle = length * width.
Then set the area expression equal to the given area, 54.
Solve the equation for w, and that is the width.
Add 3 to the width to find the length.