原式=[(x²+2xy+y²)/(5x²-4xy)]÷[(x+y)/(5x-4y)]+[(x²-y)/x]={ (x+y)²/[x(5x-4y)] }×[(5x-4y)/(x+y)]+[(x²-y)/x]=[(x+y)/x]+[(x²-y)/x]=(x+y+x²-y)/x=(x²+x)/x=x(x+1...