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

$(x+2)(x+5)$
To factor a second-degree polynomial $x^2 + 7x + 10$, we have to find integers whose product is $10$ and whose sum is $7$. That is, we have $2$ and $5$ where $2+5=7$ and $2\times 5=10$. Thus: $$x^2 + 7x + 10=(x+2)(x+5) .$$