Answer:
a = -3
Explanation:
Given the equation;
[tex]-2a\text{ - 9 = 6a+15}[/tex]Collect the like terms;
[tex]\begin{gathered} -2a-6a\text{ = 15 + 9} \\ -8a\text{ = 24} \end{gathered}[/tex]Divide bith sides by -8;
[tex]\begin{gathered} \frac{-8a}{-8}=\frac{24}{-8} \\ a\text{ = -3} \end{gathered}[/tex]Hence the solution is a = -3