[tex](2+i)^3=(i+2)^3[/tex] ↝ Properties
[tex](x+y)^3=x^3+3x^2y+3xy^2+y^3\\(i+2)^3=i^3+3(i)^2(2)+3(i)(2)^2+2^3\\(i+2)^3=i^3+6i^2+12i+8[/tex]
Proceed with define of complex number.
[tex]i=\sqrt{-1}\\i^2=-1\\i^3=-i\\i^4=1[/tex]
[tex]-i-6+12i+8\\2+11i[/tex]
Therefore, the answer is 2 + 11i
