Answer:
(x+3)m
Step-by-step explanation:
Area of a rectangle = Length × width
Given the area = (x²-9)m²
Width = (x-3)m
Length of the rectangle = Area/Width
Length of the rectangle = x²-9/x-3
= x²-3²/x-3
Note that according to different of two square, a²-b² = (a+b)(a-b)
Therefore x²-3² = (x+3)(x-3)
Length of the rectangle
= (x+3)(x-3)/x-3
= x+3
The length of the rectangle is (x+3)m