First, let's simplify the equation by combining like terms. This is done as shown:
[tex]-5a + 5a + 9 = 8[/tex]
[tex]9 = 8[/tex]
You may notice an issue. [tex]9 = 8[/tex] isn't a valid statement, which means that there are zero solutions to the equation.
The answer is Choice A, or zero.