First expand:
[tex](x+2)(x+2)(x+2)[/tex]
[tex](x^2+4x+4)(x+2)[/tex]
[tex](x^3+2x^2+4x^2+8x+4x+8)[/tex]
Now combine like terms:
[tex]x^3+6x^2+12x+8[/tex]
A coefficient is a number that is in front of an x. The number in front of the x squared term is 6.
So the answer is 6.
