## Intermediate Algebra for College Students (7th Edition)

$3$; $-\text{ }\text{ } 3x$
The given expression can be written as: $=x^3+3^3$ (a sum of two cubes) RECALL: The sum of two cubes, $a^3+b^3$, can be factored as $(a+b)(a^2-ab+b^2)$. Factor the sum of two cubes using the formula above with $a=x$ and $b=3$ to obtain: $=(x+3)(x^2-3x+3^2) \\=(x+3)(x^2-3x+9)$ Thus, the missing expressions in the given statement are: $3$; $-\text{ }\text{ } 3x$