помогите уменьшить дроби пожалуйста

1. (12a^8*x^9)/(4*a^2*x^11)=(3*a^6)/(x^2);

2. (x-y)/(x^2-y^2)=(x-y)/((x-y)*(x+y))=x+y;

3. (a^2-2*a*y+y^2)/(a-y)=(a-y)^2/(a-y)=a-y;

4.(n^2-x^2)/(n^2+2*n*x+x^2)=((n-x)*(n+x))/(n+x)^2=(n-x)/(n+x);

5.(3*c-12)/(16-c^2)=(3*(c-4))/(4^2-c^2)=(3*(c-4))/((4-c)*(4+c)= -(3)/(4+c);