Question 320516
[(x^2+6x+9) /(x^2-16)][(x-4) / (x^2+7x+12)]
..
[(x+3)^2/(x+4)(x-4) ] [(x-4)/(x+4)(x+3)]
(x+3)^2*(x-4) /(x+4)(x-4)(x+4)(x+3)
(x+3)/(x+4)^2