To simplify this expression, we can start to sum the like terms:
![2x+7x-3-9=9x-12](https://img.qammunity.org/2023/formulas/mathematics/college/suud4x0ty51vcyrecm0mu9i6mec53lki2p.png)
We can also notice that both values have the 3 as a common factor, then:
![9x-12=3\cdot(3x-4)](https://img.qammunity.org/2023/formulas/mathematics/college/dtxmdeck6zpvuh13yt7nxiv1nfz72ltc15.png)
Therefore, the expression 2x -3 + 7x - 9 is equivalent to 9x - 12 = 3*(3x - 4).
We can use the two results as a simplification of the latter expression.