(1)8a^3b^2-12ab^3+6a^3b^2c=2ab^2(4a^2-6b+3a^2c)
(2)-x^5y^3+x^3y^5=x^3y^3(y^2-x^2)=x^3y^3(y+x)(y-x)
(3)m^2+2n-mn-2m=m(m-n)-2(m-n)=(m-2)(m-n)
(4)a^2-4a+4-c^2=(a-2)^2-c^2=(a+c-2)(a-c-2)
(5)(a^2+1)^2-4a^2=(a^2+2a+1)(a^2-2a+1)=(a+1)^2(a-1)^2
(6)a^4-6a^2-27=(a^2-9)(a^+3)=(a+3)(a-3)(a^2+3)
(7)5m(x-y)^2+10n(y-x)^3=5(x-y)^2[m-2n(x-y)]=5(x-y)^2(m-2nx+2ny)