Answer: Value of w is 4 units and the equation is correct.
Step-by-step explanation:
Let width of a rectangle be 'w'.
Let length of a rectangle be '2w+2'.
Since we have given that
Area of rectangle = 40 square units.
As we know the formula for "Area = Length × Breadth" :
So, it becomes,

But dimension can't be negative.
So, w must be 4 units.
Hence, Value of w is 4 units and the equation is correct.