1) = (2x + 1 + 3x + 1 + x -2) / a = 6x / a;
2) = 5mn / 14x;
3) = y(x^2 - 4y^2)* x / 3y x( x-2y) =(x-2y)(x+2y) / 3(x-2y)=
=(x+2y) / 3.
=(x^2 - y^2) + (x+y)= (x+y)(x-y) + (x+y) =(x+y)(x-y+1);
2) =(x^3+ x^2y) - (xy^2 + y^3)=x^2(x+y) - y^2( x+y)=
=(x+y)(x^2 - y^2)=(x+y)(x+y)(x-y).
3)что-то не то с условием