Question 195423
You know that Area of rectangle is given by
{{{Area = Length * Width}}}
So
{{{4x^3-5x^2-10x-3 = Length * (4x+3)}}}
{{{(4x^3-5x^2-10x-3)/(4x+3) = Length}}}
Use this URL to solve for length --> http://www.calc101.com/webMathematica/long-divide.jsp