Answer:
[tex]a=-3[/tex]
Step-by-step explanation:
[tex]-2a-9=6a+15[/tex]
Add 9 to both sides:
[tex]-2a-9+9=6a+15+9[/tex]
[tex]-2a=6a+24[/tex]
Subtract 6a from both sides:
[tex]-2a-6a=6a+24-6a[/tex]
[tex]-8a=24[/tex]
Divide both sides by -8:
[tex]\frac{-8a}{-8}=\frac{24}{-8}[/tex]
[tex]a=-3[/tex]
