1)8a^3+c^3=(2a+c)(4a^2-2ac+c^2)
2)x^9-27=(x^3-3)(x^6+3x^3+9)
3)9ab^2-16ac^2=a(9b^2-16c^2)=a(3b-4c)(3b+4c)
4) -20xy^3+45x^3y=5xy(9x^2-4y^2)=5xy(3x-2y)(3x+2y)
1)8a^3+c^3=(2a+c)(4a^2-2ac+c^2)
2)x^9-27=(x^3-3)(x^6+3x^3+9)
3)9ab^2-16ac^2=a(9b^2-16c^2)=a(3b-4c)(3b+4c)
4) -20xy^3+45x^3y=5xy(9x^2-4y^2)=5xy(3x-2y)(3x+2y)