Answer:
The width of a rectangle is: w = x+3
Step-by-step explanation:
Given
The length of rectangle = l = 4x
The area of rectangle = A = 4x² + 12x
To determine
The width of rectangle = w = ?
We know that the formula of the area of the rectangle is
substitute A = 4x² + 12x and l = 4x in the equation to determine the width w of the rectangle
4x² + 12x = w×4x
w = [4x² + 12x] / [4x]
Factor 4x² + 12x: 4x(x+3)
w = [ 4x(x+3) ] / [4x]
w = x+3
Therefore, the width of a rectangle is: w = x+3