a)27x3+27x2+9x+1+x+1/3
=(3x+1)3+1/3(3x+1)
=(3x+1)[(3x+1)2+1/3]
=(3x+1)(9x2+6x+4/3)
b)8xy3-5xyz-24y2+15z
=(8xy3-24y2)-(5xyz-15z)
=8y2(xy-3)-5z(xy-3)
=(xy-3)(8y2-5z)
c)x4+x3+x+1
=x3(x+1)+(x+1)
=(x+1)(x3+1)
=(x+1)(x+1)(x2-x+1)
=(x+1)2(x2-x+1)
d)a6-a4-2a3+2a2
=a4(a-1)(a+1)-2a2(a-1)
=(a-1)(a5+a4-2a2)
=(a-1)(a5-a4+2a4-2a2)
=(a-1)[a4(a-1)+2a2(a-1)(a+1)]
=(a-1)(a-1)(a4+2a3+2a2)
=(a-1)2(a4+2a3+2a2)
\(x^4+x^3+x+1\)
\(=x^3\left(x+1\right)+\left(x+1\right)\)
\(=\left(x+1\right)\left(x^3+1\right)\)
\(=\left(x+1\right)^2\left(x^2-x+1\right)\)