I am trying to expand the Binomial (x - 4y)5 .

this is what I got , can someone tell me , where I went wrong or correct me.

X^5-(4^0*y^0)+x^4(4^1*y^1)+X^3-(4^2*y^2)+x^2-(4^3*y^3)+x-(4^4*y^4)+x^0-(4^5*y^5)

(x^5-1)+(x^4-4y)+(x^3-16y^2)+(x^2-64y^3)+(x-256y^4)+(1025y^5)

Thanks , AC