To solve for x means to put x on one side, and everything else on the other side.
Let's do that:
\(-ax+4b\ \textgreater \ 9\)
\(-ax \ \textgreater \ 9-4b\)
And now we have to divide with -a.
Be careful: When dividing with anything that's negative, you have to reverse the inequality.
\(x \ \textless \ \frac{9-4b}{-a}\)
Final solution:
\(x \ \textless \ \frac{4b-9}{a}\)
