2) (x²+4y²)/(x-2y)+4xy/(2y-x)=(x²+4y²)/(x-2y)-4xy/(x-2y)=(x²-4xy+4y²)/(x-2y)= =(x-2y)²/(x-2y)=x-2y;4) (9a²+4y²)/(3a-2y)+12ay/(2y-3a)=(9a²+4y²)/(3a-2y)-12ay/(3a-2y)=(9a²-2ay+4y²)/(3a-2y)=(3a-2y)²/(3a-2y)=(3a-2y)$6) (a²x²+25y²)/(ax-5y)+10axy/(5y-ax)= (a²x²+25y²)/(ax-5y)-10axy/(ax-5y)= =(a²x²-10axy+25y²)/(ax-5y)=(ax-5y)²/(ax-5y)=(ax-5y)