1) 8a^3+6a^2+3a+1=(2a+1)(4a^2-2a+1)+3a*(2a+1)=(2a+1)(4a^2+a1)
2)x^3-4x^2+20x-125=(x-5)(x^2+5x+25)-4x(x-5)=(x-5)(x^2+x+25)
3)m^4+mn^3-m^3n-n^4=m(m^3+n^3)-n(m^3+n^3)=(m^3+n^3)(m-n)=(m+n)(m-n)(m^2-mn+n^2)
4)c^4+c^3y-cy^2-y^4=c^3(c+y)-y^3(c+y)=(c+y)(c^3-y^3)=(c+y)(c-y)(c^2+cy+y^2)
1) 8a^3+6a^2+3a+1=(2a+1)(4a^2-2a+1)+3a*(2a+1)=(2a+1)(4a^2+a1)
2)x^3-4x^2+20x-125=(x-5)(x^2+5x+25)-4x(x-5)=(x-5)(x^2+x+25)
3)m^4+mn^3-m^3n-n^4=m(m^3+n^3)-n(m^3+n^3)=(m^3+n^3)(m-n)=(m+n)(m-n)(m^2-mn+n^2)
4)c^4+c^3y-cy^2-y^4=c^3(c+y)-y^3(c+y)=(c+y)(c^3-y^3)=(c+y)(c-y)(c^2+cy+y^2)