Question 211008
To simplify it, first we need to factor the numerators and the denominators.

{{{((x^2-3x-10)/(x^2+6x+8))*((x^2-x-20)/(x^2-25))}}}
={{{((x^2-3x-10)(x^2-x-20))/((x^2+6x+8)(x^2-25))}}}
={{{((x-5)(x+2)(x-5)(x+4))/((x+4)(x+2)(x+5)(x-5))}}}
={{{((x-5)cross((x+2))cross((x-5))cross((x+4)))/(cross((x+4))cross((x+2))(x+5)cross((x-5)))}}}
={{{(x-5)/(x+5)}}}