We have the expression 4x+9-6x+6 and we have to simplify it.
We can group the terms that are alike. We have two groups of terms: the ones that are multiplied by "x" and the ones that are just numbers alone.
Then, the terms 4x and (-6x) are alike and we can add them, getting (-2x). In this terms, x is the common denominator of both terms.
The other terms that are alike are 9 and 6, that can be added to get 15.
[tex]\begin{gathered} 4x+9-6x+6 \\ (4-6)x+(9+6) \\ -2x+15 \end{gathered}[/tex]The answer is -2x+15.
