Answer:
![x^2-9x+20=(x-4)(x-5)](https://img.qammunity.org/2021/formulas/mathematics/college/clofrd7cyopaxq0ixk01f94g2n8you2p0k.png)
Explanation:
Factoring a Trinomial
A second-degree trinomial can be expressed as:
![ax^2+bx+c](https://img.qammunity.org/2021/formulas/mathematics/middle-school/2l7bgpnc614y04iljycygusm3pon0vhiuh.png)
It can be factored, i.e., converted to a product instead of a sum of terms in several ways.
We'll use the grouping method.
Factor:
![x^2-9x+20](https://img.qammunity.org/2021/formulas/mathematics/college/q7bjcl8f3cwr4lp77aveywxqw0lz9fu2dx.png)
Split the second term into two terms:
![x^2-4x-5x+20](https://img.qammunity.org/2021/formulas/mathematics/college/fwcefessgwlp05k87fbd3e0ijstnhqtqqw.png)
Factor x on the first two terms and -5 on the last two terms:
![x(x-4)-5(x-4)](https://img.qammunity.org/2021/formulas/mathematics/college/qvmej6a9yaxblt497o3fxnkrvlp24mq84p.png)
Now factor out x-4:
![(x-4)(x-5)](https://img.qammunity.org/2021/formulas/mathematics/college/np7fkjjoofqda3g3r5zlq4qy0amkr94bx7.png)
Thus:
![\mathbf{x^2-9x+20=(x-4)(x-5)}](https://img.qammunity.org/2021/formulas/mathematics/college/d2rx0dg6w4936kmeaqeafkt29iwclsd0rt.png)