Question 314739
[(x^2+x+7/(x-3)(x+4)]-[(x^2+3)/(x^2+x-12)]
..
[(x^2+x+7/(x-3)(x+4)]-[(x^2+3)/(x+4)(x-3)]
LCM = (x-3)(x+4)
..
x^2+x+7 -x^2-3 / x-3)(x+4)
(x+4 )/ (x-3)(x+4)
1/(x-3)