\(8,\\ 1.A=2xy\left(x^2-y^2-2y-1\right)\\ 3.A=x^3\left(x^2-7\right)^2-36x=x\left[x^2\left(x^2-7\right)^2-36\right]\\ =x\left\{\left[x\left(x^2-7\right)-6\right]\left[x\left(x^2-7\right)+6\right]\right\}\\ =x\left(x^3-7x-6\right)\left(x^3-7x+6\right)\\ =x\left(x-3\right)\left(x+1\right)\left(x+2\right)\left(x+3\right)\left(x-2\right)\left(x-1\right)\\ 6.A=2x^4-32=2\left(x^4-16\right)\\ =2\left(x^2-4\right)\left(x^2+4\right)=2\left(x-2\right)\left(x+2\right)\left(x^2+4\right)\)
\(8.A=x^2\left(x^2-4x+4\right)=x^2\left(x-2\right)^2\\ 10.A=5\left(x^4-2x^2y^2+y^4\right)\\ =5\left(x^2-y^2\right)^2=5\left(x-y\right)^2\left(x+y\right)^2\\ 11.A=4\left(x-y\right)+\left(x-y\right)^2=\left(x-y\right)\left(4+x-y\right)\\ 12.A=x^4-\left(x^2-2x+1\right)=x^4-\left(x-1\right)^2=\left(x^2-x+1\right)\left(x^2+x-1\right)\\ 13.A=x^3-x^2-3x^2+3x+x-1=\left(x-1\right)\left(x^2-3x+1\right)\)
