To solve the equation for x, first, we add 9 from both sides:
[tex]\begin{gathered} -8x-9=-21 \\ -8x-9+9=-21+9 \\ -8x=-12 \end{gathered}[/tex]
Now, we divide by -8 from both sides of the equation:
[tex]\begin{gathered} \frac{-8x}{-8}=\frac{-12}{-8} \\ x=1.5 \end{gathered}[/tex]
Therefore, the solution of the given equation is 1.5.
