(1）1+2x/4x²+4x+1 =(1+2X)/(1+2x)^2=1/(2x+1)(2)x+xy/y²-1 =x(1+y)/(y+1)(y-1)=x/(y-1)(3)4x-x²/16-x² =x(4-x)/(4+x)(4-x)=x/(x+4)(4)x²-y²/3x²+6xy+3y² =(x+y)(x-y)/3(x+...