1. If the numbers are the same, 10n +n, or 11n
.. If the numbers are different, 10a +b
2. 5(a -b)
3. 5n = 15
The length and width of the rectangle are: 
<h3>What is the area of the rectangle?</h3>
The area of the rectangle is the product of the length and width of a given rectangle.
The area of the rectangle = length × Width
The area of a rectangle is represented by the expression
.
The area of the rectangle = 
= 
So, the length and width of the rectangle are: 
Learn more about the area;
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It is 10 to 1 significant figures