3x^2 - 4x + 2
The area of the rectangle is given by the expression 9x^3 - 12x^2 + 6x.
The width of the rectangle is 3x.
To find the length you can divide the area by the width.
Length = Area / Width
Substituting the given values
Length = (9x^3 - 12x^2 + 6x) / (3x)
simplify the expression by factoring out a common term.
Length = 3x (3x^2 - 4x + 2) / (3x)
Canceling out the common term 3x
Length = 3x^2 - 4x + 2