## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$8x^3+12x^2+6x+1$
We cube (expand) the binomial as follows: $$(2x+1)^3=(2x+1)(2x+1)(2x+1)=(2x)^3+3(2x)(1)^2+3(1)(2x)^2+(1)^3\\ = 8x^3+12x^2+6x+1 .$$