Answer
$8x^3+12x^2+6x+1$
Work Step by Step
RECALL:
The formula for the cube of a binomial $a+b$ is
$(a+b)^3=a^3+3a^2b+3ab^2+b^3$
Use the formula above with $a=2x$ and $b=1$ to obtain:
$(2x+1)^3
\\= (2x)^3 + 3(2x)^2(1) + 3(2x)(1^2) + 1^3
\\=8x^3 + 3(4x^2)+6x+1
\\=8x^3+12x^2+6x+1$
