![\large{\bf Step-by-step~explanation:}](https://img.qammunity.org/2021/formulas/mathematics/high-school/8t2blmvo20s2qmlyopjpmk0y7r4zfhlyag.png)
To simplify this expression, we combine all the like terms. We cannot solve for x because there is no equal sign and/or no value for x.
Equation: (10x² - 10x - 6) + (x + 6)
![\bf Step~1:](https://img.qammunity.org/2021/formulas/mathematics/high-school/sk6m9v6itpfdxnsbn4miuhdikaeddk5jy4.png)
-10x and x are like terms. Remember: there is an invisible 1 behind the variable x. We add these like normal numbers.
![\bf -10x+1x=-9x](https://img.qammunity.org/2021/formulas/mathematics/high-school/voooiyhdwbe7c45ytbhduv89hnwazu38ut.png)
![\bf Step~2:](https://img.qammunity.org/2021/formulas/mathematics/high-school/tplq5nrr9wx5t60ojcxwjypqpe6iy2lvmh.png)
-6 and 6 are also like terms. Again, we add them as written.
![\bf -6+6=0](https://img.qammunity.org/2021/formulas/mathematics/high-school/splf37yfyk3thxtz4nkz7xdaty6zut6rbv.png)
Since our answer is 0, we do not have to write it in our simplified expression.
![\bf Step~3:](https://img.qammunity.org/2021/formulas/mathematics/high-school/a69zr3pef9syx1haubr869l0uvfwb3hb5v.png)
Now, let's add the terms together. Since 10x² doesn't have any like terms, we just let it be. We take our previous number, -9x, and we add it to 10x².
![\bf 10x^2+-9x](https://img.qammunity.org/2021/formulas/mathematics/high-school/qq3jp7p29py4tgx1bdkxahxoqf9t0j9nh7.png)
![\large\boxed{\bf Our~final~answer:10x^2-9x}](https://img.qammunity.org/2021/formulas/mathematics/high-school/oh5p3h1ehmmbdforcbcxrtlu4cbt8pnspk.png)