Given an expression of (-6x +6) and (-3x - 7)
[tex]\text{The sum of the expression (-6x +6) and (-3x -7)}[/tex][tex]\begin{gathered} -6x\text{ + 6 + -3x -7 } \\ \text{collecting like terms} \\ -6x\text{ -3x + 6 - 7 } \\ -9x\text{ - 1} \end{gathered}[/tex]Hence the solution to the above expression is
[tex]-9x\text{ - 1}[/tex]