Question 45919
{{{((2x^2 - x - 3)/(3x^2+7x+4))*((3x^2 - 11x -20)/(4x^2-9))}}}
The first thing to do is to factor as much as possible before trying to multiply

{{{((2x-3)(x+1)/(3x+4)(x+1))*((x-5)(3x+4)/(4x^2-9))}}} After canceling we have

{{{(2x-3)(x-5)/(4x^2-9)}}} is your final answer