width = 2x-1
area = 2x^3+x^2-5x+2
length=y
since the area of a rectangle is found by multiplying the length times the width, your equation would be (2x-1)×y=2x^3+x^2-5x+2
Solve this equation by moving all the terms to the left side and set them equal to zero. After this, set each factor to zero.
Your answer would be
length= x^2+x-2