A=1+2+2^2+2^3+...+2^10

=>2A=2+2^2+2^3+2^4+...+2^11

=>2A-A=(2+2^2+2^3+...+2^11)-(1+2+2^2+...+2^10)

=>A=2^11-1

=>A=2047

Vậy A=2047

one + two = three 

K mk mk k lại ! 

x³-2x²+x

=(x³-x²)-(x²-x)

=x²(x-1)- x(x-1)

=(x-1)(x²-x)

=x(x-1)(x-1)

=x(x-1)²