Answer:
(7x + 27) units
Step-by-step explanation:
A rectangle is a quadrilateral (has four sides) in which opposite sides are equal and parallel, also all the angles are equal. The area of a rectangle is given as:
Area = Length × Width
Given that the area of the rectangle is 21x + 81 and the width is 3 unit, to find the length of the rectangle, we have to use the formula of the area and then get the length. Therefore:
Area = Length × Width
21x + 81 = Length × 3
Length = (21x + 81) /3
Length = 7x + 27
The length of the rectangle is 7x + 27 units
