1. 2x/y^4 и 3y^3/y^4
2.2by/a^5y и 6a^5y/a^5y
3.4x/6x^2y^2 и 7y/6x^2y^2
4.28x/7x(x+5) и 3x+15/7x(x+5)
5.a/2a+2 и 6/2a+2
6.8x^2+8xy/12(x^2-y^2) и 9xy-9y^2/12(x^2-y^2)
247.
a+b/(a+b)(a-b)(a^2+ab+b^2) ; a^2+ab+b^2/(a+b)(a-b)(a^2+ab+b^2) ;
(a+b)(a-b)/(a+b)(a-b)(a^2+ab+b^2)