1. А) 4а/16a^2b=1/4ab;
Б) 6x/24yx^3=1/4yx^2;
B) 4a^2b^5/12a^4b^7=1/3a^2b^2;
2. A)-4c^4/12a^6c= - c^3/3a^6;
Б) 5x^3y/55x^3y^4=1/11y^3;
B) 13xy^5/78x^5y^4=y/6x^4;
3. A) 3x-15y/4x-20y= 3(x-5y)/4(x-5y)=3/4;
Б) 4-2a/6a-12= 2(2-a)/6(a-2)= - 2(a-2)/6(a-2)=-1/3;
B) a^2+3a/15+5a= a(a+3)/5(3+a)= a/5;
7. A) 9x^2+24x+16/9x^2-16= (3x+4)^2/(3x+4)(3x-4)=3x+4/3x-4;
Б) 4y^2-28y+49/-2y^2+7y=(2y-7)^2/-y(2y-7)= 2y-7/-y;
B) a^2-18a+81/81-a^2=
(a-9)^2/(9-a)(9+a)=-(9-a)^2/(9-a)(9+a)=9-a/9+a.