\(1A,\\ a,A=x^3-2x^2-x^3+1=1-2x^2\\ b,B=\left(xy-1\right)\left(xy-1-xy-2\right)=-3\left(xy-1\right)=3-3xy\\ 1B,\\ a,M=x^3-x^2-4x+4-x^3+9x^2-27x+27=8x^2-31x+31\\ b,N=\left(xy-2\right)\left(xy-1-xy+2\right)\\ N=xy-2\\ 2A\\ a,x^2+4x+4=\left(x+2\right)^2\\ b,4x^2-12x+9=\left(2x-3\right)^2\\ c,4x^2-12xy+9y^2=\left(2x-3y\right)^2\\ d,\left(x-\dfrac{y}{2}\right)\left(x+\dfrac{y}{2}\right)=x^2-\dfrac{y^2}{4}\)
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