Answer: The correct option is
(D)
Step-by-step explanation: We are given to simplify the following expression :
![E=(3x-5)+(3x+6)~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)](https://img.qammunity.org/2020/formulas/mathematics/high-school/phhx14uqj2cf7yq4pbgqa89o3z6y721pqs.png)
To simplify the given expression, the coefficients of the terms involving x will be added and the constant will be added separately.
The simplification of expression (i) is as follows :
![E\\\\=(3x-5)+(3x+6)\\\\=3x-5+3x+6\\\\=6x+1.](https://img.qammunity.org/2020/formulas/mathematics/high-school/by4phghpeqxoi65hvqg1640a4uo4a8r43e.png)
Thus, the required simplified answer is
![6x+1.](https://img.qammunity.org/2020/formulas/mathematics/high-school/18klbtg9q1tf4457voab6db0am67w67uz2.png)
Option (D) is CORRECT.