For this case we must factor the following expression:
![x ^ 2 + 9x + 20](https://img.qammunity.org/2020/formulas/mathematics/college/jzoml44w7dkkfz296mfioptoiwwxg4egst.png)
To do this, we must find two numbers that, when multiplied, result in 20 and when added together, result is obtained 9. These numbers are 5 and 4.
![5 * 4 = 20\\5 + 4 = 9](https://img.qammunity.org/2020/formulas/mathematics/college/tl9039bfus4gpq7ocqzzxx5dp1qdzn5ou7.png)
So we have to express the expression as:
![(x + 5) (x + 4)](https://img.qammunity.org/2020/formulas/mathematics/college/tab31e684tcdmgi74mkbzex1e9t66w09pg.png)
Answer:
![(x + 5) (x + 4)](https://img.qammunity.org/2020/formulas/mathematics/college/tab31e684tcdmgi74mkbzex1e9t66w09pg.png)